This is a good article. Click here for more information.

Spanish flu

From WikiProjectMed
Jump to navigation Jump to search

Spanish flu
Soldiers from Fort Riley, Kansas, ill with Spanish flu at a hospital ward at Camp Funston
Soldiers sick with Spanish flu at a hospital ward, Camp Funston, Fort Riley, Kansas.
Virus strainStrains of A/H1N1
First outbreakUnknown
DateFebruary 1918 – April 1920[1]
Suspected cases500 million (estimated)[2]
25–50 million (generally accepted), other estimates range from 17 to 100 million[3][4][5]
Suspected cases have not been confirmed by laboratory tests as being due to this strain, although some other strains may have been ruled out.

The 1918 flu pandemic,[6] also known as the Great Influenza epidemic or by the common misnomer of the Spanish flu, was an exceptionally deadly global influenza pandemic caused by the H1N1 influenza A virus. The earliest documented case was March 1918 in Kansas, United States, with further cases recorded in France, Germany and the United Kingdom in April. Two years later, nearly a third of the global population, or an estimated 500 million people, had been infected in four successive waves. Estimates of deaths range from 17 million to 50 million,[7] and possibly as high as 100 million, making it one of the deadliest pandemics in history.

The pandemic broke out near the end of World War I, when wartime censors in the belligerent countries suppressed bad news to maintain morale, but newspapers freely reported the outbreak in neutral Spain, creating a false impression of Spain as the epicenter and leading to the "Spanish flu" misnomer.[8] Limited historical epidemiological data make the pandemic's geographic origin indeterminate, with competing hypotheses on the initial spread.[2]

Most influenza outbreaks disproportionately kill the young and old, with a higher survival rate in-between, but this pandemic had unusually high mortality for young adults.[9] Scientists offer several explanations for the high mortality, including a six-year climate anomaly affecting migration of disease vectors with increased likelihood of spread through bodies of water.[10] The virus was particularly deadly because it triggered a cytokine storm, ravaging the stronger immune system of young adults,[11] although the viral infection was apparently no more aggressive than previous influenza strains.[12][13] Malnourishment, overcrowded medical camps and hospitals, and poor hygiene, exacerbated by the war, promoted bacterial superinfection, killing most of the victims after a typically prolonged death bed.[14][15]

The 1918 Spanish flu was the first of three flu pandemics caused by H1N1 influenza A virus; the most recent one was the 2009 swine flu pandemic.[16][17] The 1977 Russian flu was also caused by H1N1 virus.[16][18]


El Sol (Madrid), 28 May 1918: "The three-day fever – In Madrid 80,000 Are Infected – H.M. the King is sick"

This pandemic was known by many different names—some old, some new—depending on place, time, and context. The etymology of alternative names historicises the scourge and its effects on people who would only learn years later that invisible viruses caused influenza.[19] This lack of scientific answers led the Sierra Leone Weekly News (Freetown) to suggest a biblical framing in July 1918, using an interrogative from Exodus 16 in ancient Hebrew:[lower-alpha 1] "One thing is for certain—the doctors are at present flabbergasted; and we suggest that rather than calling the disease influenza they should for the present until they have it in hand, say Man hu—'What is it?'"[21][22][23]

Descriptive names

Outbreaks of influenza-like illness were documented in 1916–17 at British military hospitals in Étaples, France,[24] and just across the English Channel at Aldershot, England. Clinical indications in common with the 1918 pandemic included rapid symptom progression to a "dusky" heliotrope cyanosis of the face. This characteristic blue-violet cyanosis in expiring patients led to the name 'purple death'.[25][26][27]

The Aldershot physicians later wrote in The Lancet, "the influenza pneumococcal purulent bronchitis we and others described in 1916 and 1917 is fundamentally the same condition as the influenza of this present pandemic."[28] This "purulent bronchitis" is not yet linked to the same A/H1N1 virus,[29] but it may be a precursor.[28][30][31]

In 1918, 'epidemic influenza' (Italian: influenza, influence),[32] also known at the time as 'the grip' (French: la grippe, grasp),[33] appeared in Kansas in the U.S. during late spring, and early reports from Spain began appearing on 21 May.[34][35] Reports from both places called it 'three-day fever' (fiebre de los tres días).[36][37][38]

Associative names

Front page of The Times (London), 25 June 1918: "The Spanish Influenza"

Many alternative names are exonyms in the practice of making new infectious diseases seem foreign.[39][40][41] This pattern was observed even before the 1889–1890 pandemic, also known as the 'Russian flu', when the Russians already called epidemic influenza the 'Chinese catarrh', the Germans called it the 'Russian pest', while the Italians in turn called it the 'German disease'.[42][43] These epithets were re-used in the 1918 pandemic, along with new ones.[44]

'Spanish' influenza

Advertisement in The Times, 28 June 1918 for Formamint tablets to prevent "Spanish influenza"

Outside Spain, the disease was soon misnamed 'Spanish influenza'.[45][46] In a 2 June 1918 The Times of London dispatch titled, "The Spanish Epidemic," a correspondent in Madrid reported over 100,000 victims of, "The unknown disease…clearly of a gripal character," without referring to "Spanish influenza" directly.[47] Three weeks later The Times reported that, "Everybody thinks of it as the 'Spanish' influenza to-day."[48] Three days after that an advertisement appeared in The Times for Formamint tablets to prevent "Spanish influenza".[49][50] When it reached Moscow, Pravda announced, "Ispánka (the Spanish lady) is in town," making 'the Spanish lady' another common name.[51]

The outbreak did not originate in Spain (see below),[52] but reporting did, due to wartime censorship in belligerent nations. Spain was a neutral country unconcerned with appearances of combat readiness, and without a wartime propaganda machine to prop up morale;[53][54] so its newspapers freely reported epidemic effects, including King Alfonso XIII's illness, making Spain the apparent locus of the epidemic.[55] The censorship was so effective that Spain's health officials were unaware its neighboring countries were similarly affected.[56]

In an October 1918 "Madrid Letter" to the Journal of the American Medical Association, a Spanish official protested, "we were surprised to learn that the disease was making ravages in other countries, and that people there were calling it the 'Spanish grip'. And wherefore Spanish? …this epidemic was not born in Spain, and this should be recorded as a historic vindication."[57] But before this letter could be published, The Serbian Newspaper (Corfu) said, "Various countries have been assigning the origin of this imposing guest to each other for quite some time, and at one point in time they agreed to assign its origin to the kind and neutral Spain…"[58]

"Spanish influenza," "three-day fever," "the flu." by Rupert Blue, U.S. Surgeon General, 28 September 1918

Other exonyms

French press initially used 'American flu', but adopted 'Spanish flu' in lieu of antagonizing an ally.[59] In the spring of 1918, British soldiers called it 'Flanders flu', while German soldiers used 'Flandern-Fieber' (Flemish fever), both after a famous battlefield in Belgium where many soldiers on both sides fell ill.[44][41][60][61] In Senegal it was named 'Brazilian flu', and in Brazil, 'German flu'.[62] In Spain it was also known as the 'French flu' (gripe francesa),[52][8] or the 'Naples Soldier' (Soldado de Nápoles), after a popular song from a zarzuela.[lower-alpha 2][59] Spanish flu (gripe española) is now a common name in Spain,[64] but remains controversial there.[65][66]

Other names derived from geopolitical borders and social boundaries. In Poland it was the 'Bolshevik disease',[62][67] while the Bolsheviks referred to it as the 'Kirghiz disease'.[61] Some Africans called it a 'white man's sickness', but in South Africa, white men also used the ethnophaulism 'kaffersiekte' (lit. negro disease).[44][68] Japan blamed sumo wrestlers for bringing the disease home from a match in Taiwan by calling it 'sumo flu' (Sumo Kaze), even though three top wrestlers died there.[69][70]

World Health Organization 'best practices' first published in 2015 now aim to prevent social stigma by no longer associating culturally significant names with new diseases, listing "Spanish flu" under "examples to be avoided".[71][40][72] Many authors now eschew calling this the Spanish flu,[59] instead using variations of '1918–19/20 flu/influenza pandemic'.[73][74][75]

Local names

Some language endonyms did not name specific regions or groups of people. Examples specific to this pandemic include: Northern Ndebele: 'Malibuzwe' (let enquiries be made concerning it), Swahili: 'Ugonjo huo kichwa na kukohoa na kiuno' (the disease of head and coughing and spine),[76] Yao: 'chipindupindu' (disease from seeking to make a profit in wartime), Otjiherero: 'kaapitohanga' (disease which passes through like a bullet),[77] and Persian: 'nakhushi-yi bad' (disease of the wind).[78][79]

Other names

This outbreak was also commonly known as the 'great influenza epidemic',[80][81] after the 'great war', a common name for World War I before World War II.[11] French military doctors originally called it 'disease 11' (maladie onze).[41] German doctors downplayed the severity by calling it 'pseudo influenza' (Latin: pseudo, false), while in Africa, doctors tried to get patients to take it more seriously by calling it 'influenza vera' (Latin: vera, true).[82]

A children's song from the 1889–90 flu pandemic[83] was shortened and adapted into a skipping-rope rhyme popular in 1918.[84][85] It is a metaphor for the transmissibility of 'Influenza', where that name was clipped to the apheresis 'Enza':[86][87][88]



First wave of early 1918

Seattle policemen wearing cloth face masks handed out by the American Red Cross during the Spanish flu pandemic, December 1918

The pandemic is conventionally marked as having begun on 4 March 1918 with the recording of the case of Albert Gitchell, an army cook at Camp Funston in Kansas, United States, despite there having been cases before him.[89] The disease had already been observed 200 miles (320 km) away in Haskell County as early as January 1918, prompting local doctor Loring Miner to warn the editors of the U.S. Public Health Service's academic journal Public Health Reports.[11] Within days of the 4 March first case at Camp Funston, 522 men at the camp had reported sick.[90] By 11 March 1918, the virus had reached Queens, New York.[91] Failure to take preventive measures in March/April was later criticized.[92]

As the U.S. had entered World War I, the disease quickly spread from Camp Funston, a major training ground for troops of the American Expeditionary Forces, to other U.S. Army camps and Europe, becoming an epidemic in the Midwest, East Coast, and French ports by April 1918, and reaching the Western Front by the middle of the month.[89] It then quickly spread to the rest of France, Great Britain, Italy, and Spain and in May reached Wrocław and Odessa.[89] After the signing of the Treaty of Brest-Litovsk (March 1918), Germany started releasing Russian prisoners of war, who then brought the disease to their country.[93] It reached North Africa, India, and Japan in May, and soon after had likely gone around the world as there had been recorded cases in Southeast Asia in April.[94] In June an outbreak was reported in China.[95] After reaching Australia in July, the wave started to recede.[94]

The first wave of the flu lasted from the first quarter of 1918 and was relatively mild.[96] Mortality rates were not appreciably above normal;[2] in the United States ~75,000 flu-related deaths were reported in the first six months of 1918, compared to ~63,000 deaths during the same time period in 1915.[97] In Madrid, Spain, fewer than 1,000 people died from influenza between May and June 1918.[98] There were no reported quarantines during the first quarter of 1918. However, the first wave caused a significant disruption in the military operations of World War I, with three-quarters of French troops, half the British forces, and over 900,000 German soldiers sick.[99]

Deadly second wave of late 1918

American Expeditionary Force flu patients at U.S. Army Camp Hospital no. 45 in Aix-les-Bains, France, 1918
Spanish satirical cartoon published in November 1918 depicting a "tragic game of football" between Mars, Greek god of war, and the Spanish Flu. There is a short poem as a caption which roughly translates to English as "Between flu and war, look at how they've left her, our poor Earth"
Mars, god of war, plays a "tragic game of football" with the skeleton of the Spanish flu, November 1918

The second wave began in the second half of August 1918, probably spreading to Boston, Massachusetts and Freetown, Sierra Leone, by ships from Brest, where it had likely arrived with American troops or French recruits for naval training.[99] From the Boston Navy Yard and Camp Devens (later renamed Fort Devens), about 30 miles west of Boston, other U.S. military sites were soon afflicted, as were troops being transported to Europe.[100] Helped by troop movements, it spread over the next two months to all of North America, and then to Central and South America, also reaching Brazil and the Caribbean on ships.[101] In July 1918, the Ottoman Empire saw its first cases in some soldiers.[102] From Freetown, the pandemic continued to spread through West Africa along the coast, rivers, and the colonial railways, and from railheads to more remote communities, while South Africa received it in September on ships bringing back members of the South African Native Labour Corps returning from France.[101] From there it spread around southern Africa and beyond the Zambezi, reaching Ethiopia in November.[103] On 15 September, New York City saw its first fatality from influenza.[104] The Philadelphia Liberty Loans Parade, held in Philadelphia, Pennsylvania, on 28 September 1918 to promote government bonds for World War I, resulted in 12,000 deaths after a major outbreak of the illness spread among people who had attended the parade.[105]

From Europe, the second wave swept through Russia in a southwest–northeast diagonal front, as well as being brought to Arkhangelsk by the North Russia intervention, and then spread throughout Asia following the Russian Civil War and the Trans-Siberian railway, reaching Iran (where it spread through the holy city of Mashhad), and then later India in September, as well as China and Japan in October.[106] The celebrations of the Armistice of 11 November 1918 also caused outbreaks in Lima and Nairobi, but by December the wave was mostly over.[107]

The second wave of the 1918 pandemic was much more deadly than the first. The first wave had resembled typical flu epidemics; those most at risk were the sick and elderly, while younger, healthier people recovered easily. October 1918 was the month with the highest fatality rate of the whole pandemic.[108] In the United States, ~292,000 deaths were reported between September–December 1918, compared to ~26,000 during the same time period in 1915.[97] The Netherlands reported over 40,000 deaths from influenza and acute respiratory disease. Bombay reported ~15,000 deaths in a population of 1.1 million.[109] The 1918 flu pandemic in India was especially deadly, with an estimated 12.5–20 million deaths in the last quarter of 1918 alone.[96][page needed]

Third wave of 1919

Pandemic activity persisted, in general, into 1919 in many places. This persistence in activity is possibly attributable to climate, specifically in the Northern Hemisphere, where it was winter and thus the usual time for influenza activity.[110][111] The pandemic nonetheless continued into 1919 largely independent of region and climate.[110]

Cases began to rise again in some parts of the United States as early as late November 1918,[112] with the Public Health Service issuing its first report of a "recrudescence of the disease" being felt in "widely scattered localities" in early December.[113] This resurgent activity varied across the country, however, possibly on account of differing restrictions.[111] Michigan, for example, experienced a swift resurgence of influenza that reached its peak in December, possibly as a result of the lifting of the ban on public gatherings.[114] Pandemic interventions, such as bans on public gatherings and the closing of schools, were reimposed in many places in an attempt to suppress the spread.[113]

There was "a very sudden and very marked rise in general death rate" in most cities in January 1919; nearly all experienced "some degree of recrudescence" of the flu in January and February.[115]: 153–154  Significant outbreaks occurred in cities including Los Angeles,[116] New York City,[1] Memphis, Nashville, San Francisco, and St. Louis.[117] By 21 February, with some local variation, influenza activity was reported to have been declining since mid-January in all parts of the country.[118] Following this "first great epidemic period" that had commenced in October 1918, deaths from pneumonia and influenza were "somewhat below average" in the large cities of the United States between May 1919 and January 1920.[115]:158 Nonetheless, nearly 160,000 deaths were attributed to these causes in the first six months of 1919.[119]

It was not until later in the winter and into the spring that a clearer resurgence appeared in Europe. A significant third wave had developed in England and Wales by mid-February, peaking in early March, though it did not fully subside until May.[120] France also experienced a significant wave that peaked in February, alongside the Netherlands. Norway, Finland, and Switzerland saw recrudescences of pandemic activity in March, and Sweden in April.[121]

Much of Spain was affected by "a substantial recrudescent wave" of influenza between January and April 1919.[122] Portugal experienced a resurgence in pandemic activity that lasted from March to September 1919, with the greatest impact being felt on the west coast and in the north of the country; all districts were affected between April and May specifically.[123]

Influenza entered Australia for the first time in January 1919 after a strict maritime quarantine had shielded the country through the latter part of 1918.[124] It assumed epidemic proportions first in Melbourne, peaking in mid-February.[125] The flu soon appeared in neighboring New South Wales and South Australia and then spread across the country throughout the year.[124] New South Wales experienced its first wave of infection between mid-March and late May,[126] while a second, more severe wave occurred in Victoria between April and June.[125]

Land quarantine measures hindered the spread of the disease, resulting in varied experiences of exposures and outbreaks among the various states. Queensland was not infected until late April; Western Australia avoided the disease until early June, and Tasmania remained free from it until mid-August.[124] Out of the six states, Victoria and New South Wales experienced generally more extensive epidemics. Each experienced another significant wave of illness over the winter. The second epidemic in New South Wales was more severe than the first,[126] while Victoria saw a third wave that was somewhat less extensive than its second, more akin to its first.[125]

The disease also reached other parts of the world for the first time in 1919, such as Madagascar, which saw its first cases in April; the outbreak had spread to practically all sections of the island by June.[127] In other parts, influenza recurred in the form of a true "third wave". Hong Kong experienced another outbreak in June,[128] as did South Africa during its fall and winter months in the Southern Hemisphere.[129][130][131] New Zealand also experienced some cases in May.[132]

Parts of South America experienced a resurgence of pandemic activity throughout 1919. A third wave hit Brazil between January and June.[110] Between July 1919 and February 1920, Chile, which had been affected for the first time just in October 1918, experienced a severe second wave, with mortality peaking in August 1919.[133] Montevideo similarly experienced a second outbreak between July and September.[134]

The third wave particularly affected Spain, Serbia, Mexico and Great Britain, resulting in hundreds of thousands of deaths.[135] It was in general less severe than the second wave but still much more deadly than the initial first wave.

Fourth wave of 1920

Public health recommendations from the Illustrated Current News

In the Northern Hemisphere, fears of a "recurrence" of the flu grew as fall approached. Experts cited the history of past flu epidemics, such as that of 1889–1890, to predict that such a recurrence a year later was not unlikely,[136][137] though not all agreed.[138] In September 1919, U.S. Surgeon General Rupert Blue said a return of the flu later in the year would "probably, but by no means certainly," occur.[139] France had readied a public information campaign before the end of the summer,[140] and Britain began preparations in the fall with the manufacture of vaccine.[141]

In Japan, the flu broke out again in December and spread rapidly throughout the country, a fact attributed at the time to the coming of cold weather.[142][143] Pandemic-related measures were renewed to check the spread of the outbreak, and health authorities recommended the use of masks.[143] The epidemic intensified in the latter part of December before swiftly peaking in January.[144]

Between October 1919 and 23 January 1920, 780,000 cases were reported across the country, with at least 20,000 deaths recorded by that date. This apparently reflected "a condition of severity three times greater than for the corresponding period of" 1918–1919, during Japan's first epidemic.[144] Nonetheless, the disease was regarded as being milder than it had been the year before, albeit more infectious.[145] Despite its rapid peak at the beginning of the year, the outbreak persisted throughout the winter, before subsiding in the spring.[146]

In the United States, there were "almost continuously isolated or solitary cases" of flu throughout the spring and summer months of 1919.[147] An increase in scattered cases became apparent as early as September,[148] but Chicago experienced one of the first major outbreaks of the flu beginning in the middle of January.[149] The Public Health Service announced it would take steps to "localize the epidemic",[150] but the disease was already causing a simultaneous outbreak in Kansas City and quickly spread outward from the center of the country in no clear direction.[147] A few days after its first announcement, PHS issued another assuring that the disease was under the control of state health authorities and that an outbreak of epidemic proportions was not expected.[151]

It became apparent within days of the start of Chicago's explosive growth in cases that the flu was spreading in the city at an even faster rate than in winter 1919, though fewer were dying.[152] Within a week, new cases in the city had surpassed its peak during the 1919 wave.[153] Around the same time, New York City began to see its own sudden increase in cases,[154] and other cities around the country were soon to follow.[155] Certain pandemic restrictions, such as the closing of schools and theaters and the staggering of business hours to avoid congestion, were reimposed in cities like Chicago,[156] Memphis,[157] and New York City.[158] As they had during the epidemic in fall 1918, schools in New York City remained open,[158] while those in Memphis were shuttered as part of more general restrictions on public gatherings.[157]

American Red Cross nurses tend to flu patients in temporary wards set up inside the Oakland Municipal Auditorium

The fourth wave in the United States subsided as swiftly as it had appeared, reaching a peak in early February.[159] "An epidemic of considerable proportions marked the early months of 1920", the U.S. Mortality Statistics would later note; according to data at this time, the epidemic resulted in one third as many deaths as the 1918–1919 experience.[160] New York City alone reported 6,374 deaths between December 1919 and April 1920, almost twice the number of the first wave in spring 1918.[1] Other U.S. cities including Detroit, Milwaukee, Kansas City, Minneapolis, and St. Louis were hit particularly hard, with death rates higher than all of 1918.[117] The Territory of Hawaii experienced its peak of the pandemic in early 1920, recording 1,489 deaths from flu-related causes, compared with 615 in 1918 and 796 in 1919.[161]

Poland experienced a devastating outbreak during the winter months, with its capital Warsaw reaching a peak of 158 deaths in a single week, compared to the peak of 92 reached in December 1918; however, the 1920 epidemic passed in a matter of weeks, while the 1918–1919 wave had developed over the entire second half of 1918.[162] By contrast, the outbreak in western Europe was considered "benign", with the age distribution of deaths beginning to take on that of seasonal flu.[163] Five countries in Europe (Spain, Denmark, Finland, Germany and Switzerland) recorded a late peak between January–April 1920.[121]

Mexico experienced a fourth wave between February and March. In South America, Peru experienced "asynchronous recrudescent waves" throughout the year. A severe third wave hit Lima, the capital city, between January and March, resulting in an all-cause excess mortality rate approximately four times greater than that of the 1918–1919 wave. Ica similarly experienced another severe pandemic wave in 1920, between July and October.[164] A fourth wave also occurred in Brazil, in February.[110]

Korea and Taiwan, both colonies of Japan at this time, also experienced pronounced outbreaks in late 1919 and early 1920.[165][166]


By mid-1920, the pandemic was largely considered to be "over" by the public as well as governments.[167] Though parts of Chile experienced a third, milder wave between November 1920 and March 1921,[133] the flu seemed to be mostly absent through the winter of 1920–1921.[115]:167 In the United States, for example, deaths from pneumonia and influenza were "very much lower than for many years".[115]:167

Influenza began to be reported again from many places in 1921.[115]:168 The pandemic continued to be felt in Chile, where a fourth wave affected seven of its 24 provinces between June and December 1921.[133] The winter of 1921–1922 was the first major reappearance of the disease in the Northern Hemisphere, in many parts its most significant occurrence since the main pandemic in late 1918. Northwestern Europe was particularly affected. All-cause mortality in Holland approximately doubled in January 1922 alone.[115]:168 In Helsinki, a major epidemic (the fifth since 1918) prevailed between November and December 1921.[168] The flu was also widespread in the United States, its prevalence in California reportedly greater in early March 1922 than at any point since 1920.[115]:172

In the years after 1920, the disease, a novel one in 1918, assumed a more familiar nature, coming to represent at least one form of the "seasonal flu". The virus, H1N1, remained endemic, occasionally causing more severe or otherwise notable outbreaks as it gradually evolved over the years.[169] The period since its initial appearance in 1918 has been termed a "pandemic era", in which all flu pandemics since its emergence have been caused by its own descendants.[170] Following the first of these post-1918 pandemics, in 1957, the virus was totally displaced by the novel H2N2, the reassortant product of the human H1N1 and an avian influenza virus, which thereafter became the active influenza A virus in humans.[169]

In 1977, an influenza virus bearing a very close resemblance to the seasonal H1N1 not seen since the 1950s appeared in Russia and subsequently initiated a "technical" pandemic that principally affected those 26 years of age and younger.[171][172] While some natural explanations, such as the virus remaining in some frozen state for 20 years,[172] have been proposed to explain this unprecedented[173] phenomenon, the nature of influenza itself has been cited in favor of human involvement of some kind, such as an accidental leak from a lab where the old virus had been preserved for research purposes.[172] Following this miniature pandemic, the reemerged H1N1 became endemic once again but did not displace the other active influenza A virus, H3N2 (which itself had displaced H2N2 through a pandemic in 1968).[171][169] For the first time, two influenza A viruses were observed in cocirculation.[174] This state of affairs has persisted even after 2009, when a novel H1N1 virus emerged, sparked a pandemic, and thereafter took the place of the seasonal H1N1 to circulate alongside H3N2.[174]

Potential origins

Despite its name, historical and epidemiological data cannot identify the geographic origin of the Spanish flu.[2] However, several theories have been proposed.

United States

The first confirmed cases originated in the United States. Historian Alfred W. Crosby stated in 2003 that the flu originated in Kansas,[175] and author John M. Barry described a January 1918 outbreak in Haskell County, Kansas, as the point of origin in his 2004 article.[11]

A 2018 study of tissue slides and medical reports led by evolutionary biology professor Michael Worobey found evidence against the disease originating from Kansas, as those cases were milder and had fewer deaths compared to the infections in New York City in the same period. The study did find evidence through phylogenetic analyses that the virus likely had a North American origin, though it was not conclusive. In addition, the haemagglutinin glycoproteins of the virus suggest that it originated long before 1918, and other studies suggest that the reassortment of the H1N1 virus likely occurred in or around 1915.[176]


Edvard Munch (1863–1944), Self-Portrait with the Spanish Flu (1919)
Egon Schiele (1880–1918), Die Familie, painted a few days before his death and just after the death of his wife Edith from the Spanish flu[177]

The major U.K. troop staging and hospital camp in Étaples in France has been theorized by virologist John Oxford as being at the center of the Spanish flu.[178] His study found that in late 1916 the Étaples camp was hit by the onset of a new disease with high mortality that caused symptoms similar to the flu.[179][178] According to Oxford, a similar outbreak occurred in March 1917 at army barracks in Aldershot,[180] and military pathologists later recognized these early outbreaks as the same disease as the Spanish flu.[181][178] The overcrowded camp and hospital at Étaples was an ideal environment for the spread of a respiratory virus.

The hospital treated thousands of victims of poison gas attacks, and other casualties of war, and 100,000 soldiers passed through the camp every day. It also was home to a piggery and poultry was regularly brought in from surrounding villages to feed the camp. Oxford and his team postulated that a precursor virus, harbored in birds, mutated and then migrated to pigs kept near the front.[180][181]

A report published in 2016 in the Journal of the Chinese Medical Association found evidence that the 1918 virus had been circulating in the European armies for months and possibly years before the 1918 pandemic.[182] Political scientist Andrew Price-Smith published data from the Austrian archives suggesting the influenza began in Austria in early 1917.[183]

A 2009 study in Influenza and Other Respiratory Viruses found that Spanish flu mortality simultaneously peaked within the two-month period of October and November 1918 in all fourteen European countries analyzed, which is inconsistent with the pattern that researchers would expect if the virus had originated somewhere in Europe and then spread outwards.[121]


In 1993, Claude Hannoun, the leading expert on the Spanish flu at the Pasteur Institute, asserted the precursor virus was likely to have come from China and then mutated in the United States near Boston and from there spread to Brest, France, Europe's battlefields, the rest of Europe, and the rest of the world, with Allied soldiers and sailors as the main disseminators.[184] Hannoun considered several alternative hypotheses of origin, such as Spain, Kansas, and Brest, as being possible, but not likely.[184]

In 2014, historian Mark Humphries argued that the mobilization of 96,000 Chinese laborers to work behind the British and French lines might have been the source of the pandemic. Humphries, of the Memorial University of Newfoundland in St. John's, based his conclusions on newly unearthed records. He found archival evidence that a respiratory illness that struck northern China (where the laborers came from) in November 1917 was identified a year later by Chinese health officials as identical to the Spanish flu.[185][186] Unfortunately, no tissue samples have survived for modern comparison.[187] Nevertheless, there were some reports of respiratory illness on parts of the path the laborers took to get to Europe, which also passed through North America.[187]

China was one of the few regions of the world seemingly less affected by the Spanish flu pandemic, where several studies have documented a comparatively mild flu season in 1918.[188][189][190] (Although this is disputed due to lack of data during the Warlord Period, see Around the globe.) This has led to speculation that the Spanish flu pandemic originated in China,[190][191] as the lower rates of flu mortality may be explained by the Chinese population's previously acquired immunity to the flu virus.[174][190]

A report published in 2016 in the Journal of the Chinese Medical Association found no evidence that the 1918 virus was imported to Europe via Chinese and Southeast Asian soldiers and workers and instead found evidence of its circulation in Europe before the pandemic.[182] The 2016 study found that the low flu mortality rate (an estimated one in a thousand) recorded among the Chinese and Southeast Asian workers in Europe suggests that the Asian units were not different from other Allied military units in France at the end of 1918 and, thus, were not a likely source of a new lethal virus.[182] Further evidence against the disease being spread by Chinese workers was that workers entered Europe through other routes that did not result in a detectable spread, making them unlikely to have been the original hosts.[176]

Epidemiology and pathology

Transmission and mutation

U.S. Army flu patients at Field Hospital No. 29 near Hollerich, Luxembourg 1918. As U.S. troops deployed en masse for the war effort in Europe, they carried the Spanish flu with them.
Electron micrograph of 1918 H1N1 influenza virus particles near a cell

The basic reproduction number of the virus was between 2 and 3.[192] The close quarters and massive troop movements of World War I hastened the pandemic, and probably both increased transmission and augmented mutation. The war may also have reduced people's resistance to the virus. Some speculate the soldiers' immune systems were weakened by malnourishment, as well as the stresses of combat and chemical attacks, increasing their susceptibility.[193][194] A large factor in the worldwide occurrence of the flu was increased travel. Modern transportation systems made it easier for soldiers, sailors, and civilian travelers to spread the disease.[195] Another was lies and denial by governments, leaving the population ill-prepared to handle the outbreaks.[196]

The severity of the second wave has been attributed to the circumstances of the First World War.[197] In civilian life, natural selection favors a mild strain. Those who get very ill stay home, and those mildly ill continue with their lives, preferentially spreading the mild strain. In the trenches, natural selection was reversed. Soldiers with a mild strain stayed where they were, while the severely ill were sent on crowded trains to crowded field hospitals, spreading the deadlier virus. The second wave began, and the flu quickly spread around the world again. Consequently, during modern pandemics, health officials look for deadlier strains of a virus when it reaches places with social upheaval.[198] The fact that most of those who recovered from first-wave infections had become immune showed that it must have been the same strain of flu. This was most dramatically illustrated in Copenhagen, which escaped with a combined mortality rate of just 0.29% (0.02% in the first wave and 0.27% in the second wave) because of exposure to the less-lethal first wave.[199] For the rest of the population, the second wave was far more deadly; the most vulnerable people were those like the soldiers in the trenches – adults who were young and fit.[200]

After the lethal second wave struck in late 1918, new cases dropped abruptly. In Philadelphia, for example, 4,597 people died in the week ending 16 October, but by 11 November, influenza had almost disappeared from the city. One explanation for the rapid decline in the lethality of the disease is that doctors became more effective in the prevention and treatment of pneumonia that developed after the victims had contracted the virus. However, John Barry stated in his 2004 book The Great Influenza: The Epic Story of the Deadliest Plague In History that researchers have found no evidence to support this position.[11] Another theory holds that the 1918 virus mutated extremely rapidly to a less lethal strain. Such evolution of influenza is a common occurrence: there is a tendency for pathogenic viruses to become less lethal with time, as the hosts of more dangerous strains tend to die out.[11] Some fatal cases did continue into March 1919, killing one player in the 1919 Stanley Cup Finals[citation needed]

Signs and symptoms

US Army symptomology of the flu

The majority of the infected experienced only the typical flu symptoms of sore throat, headache, and fever, especially during the first wave.[201] However, during the second wave, the disease was much more serious, often complicated by bacterial pneumonia, which was often the cause of death.[201] This more serious type would cause heliotrope cyanosis to develop, whereby the skin would first develop two mahogany spots over the cheekbones which would then over a few hours spread to color the entire face blue, followed by black coloration first in the extremities and then further spreading to the limbs and the torso.[201] After this, death would follow within hours or days due to the lungs being filled with fluids.[201] Other signs and symptoms reported included spontaneous mouth and nosebleeds, miscarriages for pregnant women, a peculiar smell, teeth, and hair falling, delirium, dizziness, insomnia, loss of hearing or smell, and impaired vision.[201] One observer wrote, "One of the most striking of the complications was hemorrhage from mucous membranes, especially from the nose, stomach, and intestine. Bleeding from the ears and petechial hemorrhages in the skin also occurred".[202] The severity of the symptoms was believed to be caused by cytokine storms.[96]

The majority of deaths were from bacterial pneumonia,[203][204][205] a common secondary infection associated with influenza. This pneumonia was itself caused by common upper respiratory-tract bacteria, which were able to get into the lungs via the damaged bronchial tubes of the victims.[206] The virus also killed people directly by causing massive hemorrhages and edema in the lungs.[205] Modern analysis has shown the virus to be particularly deadly because it triggers a cytokine storm (overreaction of the body's immune system).[11] One group of researchers recovered the virus from the bodies of frozen victims and transfected animals with it. The animals suffered rapidly progressive respiratory failure and death through a cytokine storm. The strong immune reactions of young adults were postulated to have ravaged the body, whereas the weaker immune reactions of children and middle-aged adults resulted in fewer deaths among those groups.[207]


Because the virus that caused the disease was too small to be seen under a microscope at the time, there were problems with correctly diagnosing it.[208] The bacterium Haemophilus influenzae was instead mistakenly thought to be the cause, as it was big enough to be seen and was present in many, though not all, patients.[208] For this reason, a vaccine that was used against that bacillus did not make an infection rarer but did decrease the death rate.[209]

During the deadly second wave there were also fears that it was in fact plague, dengue fever, or cholera.[210] Another common misdiagnosis was typhus, which was common in circumstances of social upheaval, and was therefore also affecting Russia in the aftermath of the October Revolution.[210] In Chile, the view of the country's elite was that the nation was in severe decline, and therefore doctors assumed that the disease was typhus caused by poor hygiene, and not an infectious one, causing a mismanaged response which did not ban mass gatherings.[210]

The role of climate conditions

Poster with the slogan: "Coughs and sneezes spread diseases"

Studies have shown that the immune system of Spanish flu victims was weakened by adverse climate conditions which were particularly unseasonably cold and wet for extended periods of time during the duration of the pandemic. This affected especially WWI troops exposed to incessant rains and lower-than-average temperatures for the duration of the conflict, and especially during the second wave of the pandemic. Ultra-high-resolution climate data combined with highly detailed mortality records analyzed at Harvard University and the Climate Change Institute at the University of Maine identified a severe climate anomaly that impacted Europe from 1914 to 1919, with several environmental indicators directly influencing the severity and spread of the Spanish flu pandemic.[10] Specifically, a significant increase in precipitation affected all of Europe during the second wave of the pandemic, from September to December 1918. Mortality figures follow closely the concurrent increase in precipitation and decrease in temperatures. Several explanations have been proposed for this, including the fact that lower temperatures and increased precipitation provided ideal conditions for virus replication and transmission, while also negatively affecting the immune systems of soldiers and other people exposed to the inclement weather, a factor proven to increase likelihood of infection by both viruses and pneumococcal co-morbid infections documented to have affected a large percentage of pandemic victims (one fifth of them, with a 36% mortality rate).[211][212][213][214][215] A six-year climate anomaly (1914–1919) brought cold, marine air to Europe, drastically changing its weather, as documented by eyewitness accounts and instrumental records, reaching as far as the Gallipoli campaign, in Turkey, where ANZAC troops suffered extremely cold temperatures despite the normally Mediterranean climate of the region. The climate anomaly likely influenced the migration of H1N1 avian vectors which contaminate bodies of water with their droppings, reaching 60% infection rates in autumn.[216][217][218] The climate anomaly has been associated with an anthropogenic increase in atmospheric dust, due to the incessant bombardment; increased nucleation due to dust particles (cloud condensation nuclei) contributed to increased precipitation.[219][220][221]


Public health management

Coromandel Hospital Board (New Zealand) advice to influenza sufferers (1918)
In September 1918, the Red Cross recommended two-layer gauze masks to halt the spread of "plague".[222]
1918 Chicago newspaper headlines reflect mitigation strategies such as increased ventilation, arrests for not wearing face masks, sequenced inoculations, limitations on crowd size, selective closing of businesses, curfews, and lockdowns.[223] After October's strict containment measures showed some success, Armistice Day celebrations in November and relaxed attitudes by Thanksgiving caused a resurgence.[223]

While systems for alerting public health authorities of infectious spread did exist in 1918, they did not generally include influenza, leading to a delayed response.[224] Nevertheless, actions were taken. Maritime quarantines were declared on islands such as Iceland, Australia, and American Samoa, saving many lives.[224] Social distancing measures were introduced, for example closing schools, theatres, and places of worship, limiting public transportation, and banning mass gatherings.[225] Wearing face masks became common in some places, such as Japan, though there were debates over their efficacy.[225] There was also some resistance to their use, as exemplified by the Anti-Mask League of San Francisco. Vaccines were also developed, but as these were based on bacteria and not the actual virus, they could only help with secondary infections.[225] The actual enforcement of various restrictions varied.[226] To a large extent, the New York City health commissioner ordered businesses to open and close on staggered shifts to avoid overcrowding on the subways.[227]

A later study found that measures such as banning mass gatherings and requiring the wearing of face masks could cut the death rate up to 50 percent, but this was dependent on their being imposed early in the outbreak and not being lifted prematurely.[228]

Medical treatment

As there were no antiviral drugs to treat the virus, and no antibiotics to treat the secondary bacterial infections, doctors would rely on a random assortment of medicines with varying degrees of effectiveness, such as aspirin, quinine, arsenics, digitalis, strychnine, epsom salts, castor oil, and iodine.[229] Treatments of traditional medicine, such as bloodletting, ayurveda, and kampo were also applied.[230]

Information dissemination

Due to World War I, many countries engaged in wartime censorship, and suppressed reporting of the pandemic.[231] For example, the Italian newspaper Corriere della Sera was prohibited from reporting daily death tolls.[232] The newspapers of the time were also generally paternalistic and worried about mass panic.[232] Misinformation also spread along with the disease. In Ireland there was a belief that noxious gases were rising from the mass graves of Flanders Fields and being "blown all over the world by winds".[233] There were also rumors that the Germans were behind it, for example by poisoning the aspirin manufactured by Bayer, or by releasing poison gas from U-boats.[234]


Around the globe

Difference between the flu mortality age-distributions of the 1918 pandemic and normal epidemics – deaths per 100,000 persons in each age group, United States, for the interpandemic years 1911–1917 (dashed line) and the pandemic year 1918 (solid line)[235]
Three pandemic waves: weekly combined flu and pneumonia mortality, United Kingdom, 1918–1919[236]

The Spanish flu infected around 500 million people, about one-third of the world's population.[2] Estimates as to how many infected people died vary greatly, but the flu is regardless considered to be one of the deadliest pandemics in history.[237][238] An early estimate from 1927 put global mortality at 21.6 million.[4] An estimate from 1991 states that the virus killed between 25 and 39 million people.[96] A 2005 estimate put the death toll at 50 million (about 3% of the global population), and possibly as high as 100 million (more than 5%).[202][239] However, a 2018 reassessment in the American Journal of Epidemiology estimated the total to be about 17 million,[4] though this has been contested.[240] With a world population of 1.8 to 1.9 billion,[241] these estimates correspond to between 1 and 6 percent of the population.

A 2009 study in Influenza and Other Respiratory Viruses based on data from fourteen European countries estimated a total of 2.64 million excess deaths in Europe attributable to the Spanish flu during the major 1918–1919 phase of the pandemic, in line with the three prior studies from 1991, 2002, and 2006 that calculated a European death toll of between 2 million and 2.3 million. This represents a mortality rate of about 1.1% of the European population (c. 250 million in 1918), considerably higher than the mortality rate in the U.S., which the authors hypothesize is likely due to the severe effects of the war in Europe.[121] The excess mortality rate in the U.K. has been estimated at 0.28%–0.4%, far below this European average.[4]

Some 12–17 million people died in India, about 5% of the population.[242] The death toll in India's British-ruled districts was 13.88 million.[243] Another estimate gives at least 12 million dead.[244] The decade between 1911 and 1921 was the only census period in which India's population fell, mostly due to devastation of the Spanish flu pandemic.[245][246] While India is generally described as the country most severely affected by the Spanish flu, at least one study argues that other factors may partially account for the very high excess mortality rates observed in 1918, citing unusually high 1917 mortality and wide regional variation (ranging from 0.47% to 6.66%).[4] A 2006 study in The Lancet also noted that Indian provinces had excess mortality rates ranging from 2.1% to 7.8%, stating: "Commentators at the time attributed this huge variation to differences in nutritional status and diurnal fluctuations in temperature."[247]

In Finland, 20,000 died out of 210,000 infected.[248] In Sweden, 34,000 died.[249]

In Japan, the flu killed nearly 500,000 people over two waves between 1918 and 1920, with nearly 300,000 excess deaths between October 1918 and May 1919 and 182,000 between December 1919 and May 1920.[146]

In the Dutch East Indies (now Indonesia), 1.5 million were assumed to have died among 30 million inhabitants.[250] In Tahiti, 13% of the population died during one month. Similarly, in Western Samoa 22% of the population of 38,000 died within two months.[251]

In Istanbul, capital of the Ottoman Empire, 6,403[252] to 10,000[102] died, giving the city a mortality rate of at least 0.56%.[252]

In New Zealand, the flu killed an estimated 6,400 Pakeha (or "New Zealanders primarily of European descent") and 2,500 indigenous Maori in six weeks, with Māori dying at eight times the rate of Pakeha.[253][254]

In Australia, the flu killed around 12,000[255] to 20,000 people.[256] The country's death rate, 2.7 per 1,000 people, was one of the lowest recorded compared with other countries at the time; however, as much as 40 percent of the population were infected, and a mortality rate of 50 percent was recorded by some Aboriginal communities.[257][256] New South Wales and Victoria saw the greatest relative mortality, with 3.19 and 2.40 deaths per 1,000 people respectively, while Western Australia, Queensland, Southern Australia, and Tasmania experienced rates of 1.70, 1.14, 1.13, and 1.09 per 1,000 respectively. In Queensland, at least one-third of deaths recorded were in the Aboriginal population.[125]

In the U.S., about 28% of the population of 105 million became infected, and 500,000 to 850,000 died (0.48 to 0.81 percent of the population).[258][259][260] Native American tribes were particularly hard hit. In the Four Corners area, there were 3,293 registered deaths among Native Americans.[261] Entire Inuit and Alaskan Native village communities died in Alaska.[262] In Canada, 50,000 died.[263]

In Brazil, 300,000 died, including president Rodrigues Alves.[264]

In Britain, as many as 250,000 died; in France, more than 400,000.[265]

In Ghana, the influenza epidemic killed at least 100,000 people.[266] Tafari Makonnen (the future Haile Selassie, Emperor of Ethiopia) was one of the first Ethiopians who contracted influenza but survived.[267][268] Many of his subjects did not; estimates for fatalities in the capital city, Addis Ababa, range from 5,000 to 10,000, or higher.[269]

The death toll in Russia has been estimated at 450,000, though the epidemiologists who suggested this number called it a "shot in the dark".[96] If it is correct, Russia lost roughly 0.4% of its population, meaning it suffered the lowest influenza-related mortality in Europe. Another study considers this number unlikely, given that the country was in the grip of a civil war, and the infrastructure of daily life had broken down; the study suggests that Russia's death toll was closer to 2%, or 2.7 million people.[270]

Devastated communities

Deaths from all causes for New York, London, Paris, and Berlin with peaks in October and November 1918

Even in areas where mortality was low, so many adults were incapacitated that much of everyday life was hampered. Some communities closed all stores or required customers to leave orders outside. There were reports that healthcare workers could not tend the sick nor the gravediggers bury the dead because they too were ill. Mass graves were dug by steam shovel and bodies buried without coffins in many places.[271]

Bristol Bay, a region of Alaska populated by indigenous people, suffered a death rate of 40 percent of the total population, with some villages entirely disappearing.[272]

Nenana, Alaska, managed to avoid the extent of the pandemic between 1918 and 1919, but the flu at last reached the town in spring 1920. Reports suggested that during the first two weeks of May, the majority of the town's population became infected; 10% of the population were estimated to have died, most of whom were Alaska Natives.[273]

Several Pacific island territories were hit particularly hard. The pandemic reached them from New Zealand, which was too slow to implement measures to prevent ships, such as Talune, carrying the flu from leaving its ports. From New Zealand, the flu reached Tonga (killing 8% of the population), Nauru (16%), and Fiji (5%, 9,000 people).[274] Worst affected was Western Samoa, formerly German Samoa, which had been occupied by New Zealand in 1914. 90% of the population was infected; 30% of adult men, 22% of adult women, and 10% of children died. By contrast, Governor John Martin Poyer prevented the flu from reaching neighboring American Samoa by imposing a blockade.[274] The disease spread fastest through the higher social classes among the indigenous peoples, because of the custom of gathering oral tradition from chiefs on their deathbeds; many community elders were infected through this process.[275]

In Iran, the mortality was very high: according to an estimate, between 902,400 and 2,431,000, or 8% to 22% of the total population died.[276] The country was going through the Persian famine of 1917–1919 concurrently.

In Ireland, during the worst 12 months, the Spanish flu accounted for one-third of all deaths.[277][278]

In South Africa it is estimated that about 300,000 people amounting to 6% of the population died within six weeks. Government actions in the early stages of the virus' arrival in the country in September 1918 are believed to have unintentionally accelerated its spread throughout the country.[279] Almost a quarter of the working population of Kimberley, consisting of workers in the diamond mines, died.[280] In British Somaliland, one official estimated that 7% of the native population died.[281] This huge death toll resulted from an extremely high infection rate of up to 50% and the extreme severity of the symptoms, suspected to be caused by cytokine storms.[96]

Less-affected areas

In the Pacific, American Samoa[282] and the French colony of New Caledonia[283] succeeded in preventing even a single death from influenza through effective quarantines. However, the outbreak was delayed into 1926 for American Samoa and 1921 for New Caledonia as the quarantine period ended.[284] On American Samoa, at least 25% of the island residents were clinically attacked and 0.1% died, and on New Caledonia, there was widespread illness and 0.1% population died.[284] Australia also managed to avoid the first two waves with a quarantine.[224] Iceland protected a third of its population from exposure by blocking the main road of the island.[224] By the end of the pandemic, the isolated island of Marajó, in Brazil's Amazon River Delta had not reported an outbreak.[285] Saint Helena also reported no deaths.[286]

Japanese women in Tokyo during the Spanish flu pandemic, 1919

Estimates for the death toll in China have varied widely,[287][96] a range which reflects the lack of centralized collection of health data at the time due to the Warlord period. China may have experienced a relatively mild flu season in 1918 compared to other areas of the world.[190][174][288] However, some reports from its interior suggest that mortality rates from influenza were perhaps higher in at least a few locations in China in 1918.[270] At the very least, there is little evidence that China as a whole was seriously affected by the flu compared to other countries in the world.[289]

The first estimate of the Chinese death toll was made in 1991 by Patterson and Pyle, which estimated a toll of between 5 and 9 million. However, this 1991 study was criticized by later studies due to flawed methodology, and newer studies have published estimates of a far lower mortality rate in China.[188][290] For instance, Iijima in 1998 estimates the death toll in China to be between 1 and 1.28 million based on data available from Chinese port cities.[291] The lower estimates of the Chinese death toll are based on the low mortality rates that were found in Chinese port cities (for example, Hong Kong) and on the assumption that poor communications prevented the flu from penetrating the interior of China.[287] However, some contemporary newspaper and post office reports, as well as reports from missionary doctors, suggest that the flu did penetrate the Chinese interior and that influenza was severe in at least some locations in the countryside of China.[270]

Although medical records from China's interior are lacking, extensive medical data were recorded in Chinese port cities, such as then British-controlled Hong Kong, Canton, Peking, Harbin and Shanghai. These data were collected by the Chinese Maritime Customs Service, which was largely staffed by non-Chinese foreigners, such as the British, French, and other European colonial officials in China.[292] As a whole, data from China's port cities show low mortality rates compared to other cities in Asia.[292] For example, the British authorities at Hong Kong and Canton reported a mortality rate from influenza at a rate of 0.25% and 0.32%, much lower than the reported mortality rate of other cities in Asia, such as Calcutta or Bombay, where influenza was much more devastating.[292] Similarly, in the city of Shanghai – which had a population of over 2 million in 1918 – there were only 266 recorded deaths from influenza among the Chinese population in 1918.[292] If extrapolated from the extensive data recorded from Chinese cities, the suggested mortality rate from influenza in China as a whole in 1918 was likely lower than 1% – much lower than the world average (which was around 3–5%).[292] In contrast, Japan and Taiwan had reported a mortality rate from influenza around 0.45% and 0.69% respectively, higher than the mortality rate collected from data in Chinese port cities, such as Hong Kong (0.25%), Canton (0.32%), and Shanghai.[292]

However, it is noted that the influenza mortality rate in Hong Kong and Canton are under-recorded, because only the deaths that occurred in colony hospitals were counted.[292] Similarly, in Shanghai, these statistics are limited to that area of the city under the control of the health section of the Shanghai International Settlement, and the actual death toll in Shanghai was much higher.[292] The medical records from China's interior indicate that, compared to cities, rural communities have substantially higher mortality rate.[293] A published influenza survey in Houlu County, Hebei Province, found that the case fatality rate was 9.77% and 0.79% of county population died from influenza in October and November 1918.[294]

Patterns of fatality

A nurse wears a cloth face mask while treating a flu patient in Washington, DC, c. 1919

The pandemic mostly killed young adults. In 1918–1919, 99% of pandemic influenza deaths in the U.S. occurred in people under 65, and nearly half of deaths were in young adults 20 to 40 years old. In 1920, the mortality rate among people under 65 had decreased sixfold to half the mortality rate of people over 65, but 92% of deaths still occurred in people under 65.[295] This is unusual since influenza is typically most deadly to weak individuals, such as infants under age two, adults over age 70, and the immunocompromised. In 1918, older adults may have had partial protection caused by exposure to the 1889–1890 flu pandemic, known as the "Russian flu".[296] According to historian John M. Barry, the most vulnerable of all – "those most likely, of the most likely", to die – were pregnant women. He reported that in thirteen studies of hospitalized women in the pandemic, the death rate ranged from 23% to 71%.[297] Of the pregnant women who survived childbirth, over one-quarter (26%) lost the child.[298] Another oddity was that the outbreak was widespread in the summer and autumn (in the Northern Hemisphere); influenza is usually worse in winter.[299]

There were also geographic patterns to the disease's fatality. Some parts of Asia had 30 times higher death rates than some parts of Europe, and generally, Africa and Asia had higher rates, while Europe and North America had lower ones.[300] There was also great variation within continents, with three times higher mortality in Hungary and Spain compared to Denmark, two to three times higher chance of death in Sub-Saharan Africa compared to North Africa, and possibly up to ten times higher rates between the extremes of Asia.[300] Cities were affected worse than rural areas.[300] There were also differences between cities, which might have reflected exposure to the milder first wave giving immunity, as well as the introduction of social distancing measures.[301]

Another major pattern was the differences between social classes. In Oslo, death rates were inversely correlated with apartment size, as the poorer people living in smaller apartments died at a higher rate.[302] Social status was also reflected in the higher mortality among immigrant communities, with Italian Americans, a recently arrived group at the time, were nearly twice as likely to die compared to the average Americans.[300] These disparities reflected worse diets, crowded living conditions, and problems accessing healthcare.[300] Paradoxically, however, African Americans were relatively spared by the pandemic.[300]

More men than women were killed by the flu, as they were more likely to go out and be exposed, while women would tend to stay at home.[301] For the same reason men also were more likely to have pre-existing tuberculosis, which severely worsened the chances of recovery.[301] However, in India the opposite was true, potentially because Indian women were neglected with poorer nutrition, and were expected to care for the sick.[301]

A study conducted by He et al. (2011) used a mechanistic modeling approach to study the three waves of the 1918 influenza pandemic. They examined the factors that underlie variability in temporal patterns and their correlation to patterns of mortality and morbidity. Their analysis suggests that temporal variations in transmission rate provide the best explanation, and the variation in transmission required to generate these three waves is within biologically plausible values.[303] Another study by He et al. (2013) used a simple epidemic model incorporating three factors to infer the cause of the three waves of the 1918 influenza pandemic. These factors were school opening and closing, temperature changes throughout the outbreak, and human behavioral changes in response to the outbreak. Their modeling results showed that all three factors are important, but human behavioral responses showed the most significant effects.[304]


World War I

Academic Andrew Price-Smith has made the argument that the virus helped tip the balance of power in the latter days of the war towards the Allied cause. He provides data that the viral waves hit the Central Powers before the Allied powers and that both morbidity and mortality in Germany and Austria were considerably higher than in Britain and France.[183] A 2006 Lancet study corroborates higher excess mortality rates in Germany (0.76%) and Austria (1.61%) compared to Britain (0.34%) and France (0.75%).[247]

Kenneth Kahn at Oxford University Computing Services writes that "Many researchers have suggested that the conditions of the war significantly aided the spread of the disease. And others have argued that the course of the war (and subsequent peace treaty) was influenced by the pandemic." Kahn has developed a model that can be used on home computers to test these theories.[305]


Provincial Board of Health poster from Alberta, Canada

Many businesses in the entertainment and service industries suffered losses in revenue, while the healthcare industry reported profit gains.[306] Historian Nancy Bristow has argued that the pandemic, when combined with the increasing number of women attending college, contributed to the success of women in the field of nursing. This was due in part to the failure of medical doctors, who were predominantly men, to contain and prevent the illness. Nursing staff, who were mainly women, celebrated the success of their patient care and did not associate the spread of the disease with their work.[307]

A 2020 study found that U.S. cities that implemented early and extensive non-medical measures (quarantine, etc.) suffered no additional adverse economic effects due to implementing those measures.[308][309] However, the validity of this study has been questioned because of the coincidence of WWI and other problems with data reliability.[310]

Long-term effects

A 2006 study in the Journal of Political Economy found that "cohorts in utero during the pandemic displayed reduced educational attainment, increased rates of physical disability, lower income, lower socioeconomic status, and higher transfer payments received compared with other birth cohorts."[311] A 2018 study found that the pandemic reduced educational attainment in populations.[312] The flu has also been linked to the outbreak of encephalitis lethargica in the 1920s.[313]

Survivors faced an elevated mortality risk. Some survivors did not fully recover from physiological conditions resulting from infection.[314]


Mass burial site of flu victims from 1918 in Auckland, New Zealand

Despite the high morbidity and mortality rates that resulted from the epidemic, the Spanish flu began to fade from public awareness over the decades until the arrival of news about bird flu and other pandemics in the 1990s and 2000s.[315][316] This has led some historians to label the Spanish flu a "forgotten pandemic".[175] However, this label has been challenged by the historian Guy Beiner, who has charted a complex history of social and cultural forgetting, demonstrating how the pandemic was overshadowed by the commemoration of the First World War and mostly neglected in mainstream historiography, yet was remembered in private and local traditions across the globe.[317]

There are various theories of why the Spanish flu was "forgotten". The rapid pace of the pandemic, which killed most of its victims in the United States within less than nine months, resulted in limited media coverage. The general population was familiar with patterns of pandemic disease in the late 19th and early 20th centuries: typhoid, yellow fever, diphtheria, and cholera all occurred near the same time. These outbreaks probably lessened the significance of the influenza pandemic for the public.[318] In some areas, the flu was not reported on, the only mention being that of advertisements for medicines claiming to cure it.[319]

Additionally, the outbreak coincided with the deaths and media focus on the First World War.[320] Another explanation involves the age group affected by the disease. The majority of fatalities, from both the war and the epidemic, were among young adults. The high number of war-related deaths of young adults may have overshadowed the deaths caused by flu.[295]

When people read the obituaries, they saw the war or postwar deaths and the deaths from the influenza side by side. Particularly in Europe, where the war's toll was high, the flu may not have had a tremendous psychological impact or may have seemed an extension of the war's tragedies.[295] The duration of the pandemic and the war could have also played a role. The disease would usually only affect a particular area for a month before leaving.[citation needed] The war, however, had initially been expected to end quickly but lasted for four years by the time the pandemic struck.

In literature and other media

The Spanish flu has been represented in numerous works of fiction:

Mary McCarthy refers to it in her memoir Memories of a Catholic Girlhood (1957), as she and her three brothers were orphaned by their parents' deaths from the Spanish flu.

Comparison with other pandemics

The Spanish flu killed a much lower percentage of the world's population than the Black Death, which lasted for many more years.[323]

In the ongoing COVID-19 pandemic, as of 10 March 2023, more than 676 million cases have been identified and more than 6.88 million deaths recorded worldwide.[324]

Major modern influenza pandemics[325][326]
Name Date World pop. Subtype Reproduction number Infected (est.) Deaths worldwide Case fatality rate Pandemic severity
1889–90 flu pandemic[327] 1889–90 1.53 billion Likely H3N8 or H2N2 2.10 (IQR, 1.9–2.4)[327] 20–60%[327] (300–900 million) 1 million[328] 0.10–0.28%[327] 2
1918 flu[329] 1918–20 1.80 billion H1N1 1.80 (IQR, 1.47–2.27)[330] 33% (500 million)[331] or >56% (>1 billion)[332] 17[333]–100[334][335] million 2–3%,[332] or ~4%, or ~10%[336] 5
Asian flu[337] 1957–58 2.90 billion H2N2 1.65 (IQR, 1.53–1.70)[330] >17% (>500 million)[332] 1–4 million[332] <0.2%[332] 2
Hong Kong flu[338] 1968–69 3.53 billion H3N2 1.80 (IQR, 1.56–1.85)[330] >14% (>500 million)[332] 1–4 million[332] <0.1%[332][339] 2
2009 flu pandemic[340][341] 2009–10 6.85 billion H1N1/09 1.46 (IQR, 1.30–1.70)[330] 11–21% (0.7–1.4 billion)[342] 151,700–575,400[343] 0.01%[344][345] 1
Typical seasonal flu[t 1] Every year 7.75 billion A/H3N2, A/H1N1, B, ... 1.28 (IQR, 1.19–1.37)[330] 5–15% (340 million – 1 billion)[346]
3–11% or 5–20%[347][348] (240 million – 1.6 billion)
290,000–650,000/year[349] <0.1%[350] 1
  1. Not necessarily pandemic, but included for comparison purposes.


An electron micrograph showing recreated 1918 influenza virions

The origin of the Spanish flu pandemic, and the relationship between the near-simultaneous outbreaks in humans and swine, have been controversial. One hypothesis is that the virus strain originated at Fort Riley, Kansas, in viruses in poultry and swine which the fort bred for food; the soldiers were then sent from Fort Riley around the world, where they spread the disease.[351] Similarities between a reconstruction of the virus and avian viruses, combined with the human pandemic preceding the first reports of influenza in swine, led researchers to conclude the influenza virus jumped directly from birds to humans, and swine caught the disease from humans.[352][353]

Others have disagreed,[354] and more recent research has suggested the strain may have originated in a nonhuman, mammalian species.[355] An estimated date for its appearance in mammalian hosts has been put at the period 1882–1913.[356] This ancestor virus diverged about 1913–1915 into two clades (or biological groups each descended from a common ancestor), which gave rise to the classical swine and human H1N1 influenza lineages. The last common ancestor of human strains dates between February 1917 and April 1918. Because pigs are more readily infected with avian influenza viruses than are humans, they were suggested as the original recipients of the virus, passing the virus to humans sometime between 1913 and 1918.

Microbiologist examines a reconstructed version of the Spanish flu virus at the CDC

An effort to recreate the Spanish flu strain (a subtype of avian strain H1N1) was a collaboration among the Armed Forces Institute of Pathology, the USDA ARS Southeast Poultry Research Laboratory, and Mount Sinai School of Medicine in New York City. The effort resulted in the announcement (on 5 October 2005) that the group had successfully determined the virus's genetic sequence, using historic tissue samples recovered by pathologist Johan Hultin from an Inuit female flu victim buried in the Alaskan permafrost and samples preserved from American soldiers[357] Roscoe Vaughan and James Downs.[358][359]

On 18 January 2007, Kobasa et al. (2007) reported that monkeys (Macaca fascicularis) infected with the recreated flu strain exhibited classic symptoms of the 1918 pandemic, and died from cytokine storms[360] – an overreaction of the immune system. This may explain why the Spanish flu had its surprising effect on younger, healthier people, as a person with a stronger immune system would potentially have a stronger overreaction.[361]

On 16 September 2008, the body of British politician and diplomat Sir Mark Sykes was exhumed to study the RNA of the flu virus in efforts to understand the genetic structure of modern H5N1 bird flu. Sykes had been buried in 1919 in a lead coffin which scientists hoped had helped preserve the virus.[362] The coffin was found to be split and the cadaver badly decomposed; nonetheless, samples of lung and brain tissue were taken.[363]

In December 2008, research by Yoshihiro Kawaoka of the University of Wisconsin linked the presence of three specific genes (termed PA, PB1, and PB2) and a nucleoprotein derived from Spanish flu samples to the ability of the flu virus to invade the lungs and cause pneumonia. The combination triggered similar symptoms in animal testing.[364]

In June 2010, a team at the Mount Sinai School of Medicine reported the 2009 flu pandemic vaccine provided some cross-protection against the Spanish flu pandemic strain.[365]

One of the few things known for certain about influenza in 1918 and for some years after was that it was, except in the laboratory, exclusively a disease of human beings.[366]

In 2013, the AIR Worldwide Research and Modeling Group "characterized the historic 1918 pandemic and estimated the effects of a similar pandemic occurring today using the AIR Pandemic Flu Model". In the model, "a modern-day 'Spanish flu' event would result in additional life insurance losses of between US$15.3–27.8 billion in the United States alone", with 188,000–337,000 deaths in the United States.[367]

In 2018, Michael Worobey, an evolutionary biology professor at the University of Arizona who is examining the history of the 1918 pandemic, revealed that he obtained tissue slides created by William Rolland, a physician who reported on a respiratory illness likely to be the virus while a pathologist in the British military during World War One.[368] Rolland had authored an article in the Lancet during 1917 about a respiratory illness outbreak beginning in 1916 in Étaples, France.[369][370] Worobey traced recent references to that article to family members who had retained slides that Rolland had prepared during that time. Worobey extracted tissue from the slides to potentially reveal more about the origin of the pathogen.[29]

In 2021 an investigation[371] used the virus sequence[353] to obtain the Hemagglutinin (HA) antigen and observe the adaptive immunity in 32 survivors of the 1918 flu pandemic, all of them presented seroreactivity and 7 of 8 further tested presented memory B cells able to produce antibodies that bound to the HA antigen highlighting the ability of the immunological memory many decades after.

Sex differences in mortality

The high mortality rate of the influenza pandemic is one aspect that sets the pandemic apart from other disease outbreaks. Another factor is the higher mortality rate of men compared with women. Men with an underlying condition were at significantly more risk. Tuberculosis was one of the deadliest diseases in the 1900s, and killed more men than women. But with the spread of influenza disease, the cases of tuberculosis cases in men decreased. Many scholars have noted that tuberculosis increased the mortality rate of influenza in males, decreasing their life expectancy. During the 1900s tuberculosis was more common in males than females, but studies show that when influenza spread the tuberculosis mortality rate among females changed. The death rate of tuberculosis in females increased significantly and would continue to decline until post-pandemic.[372]

Death rates were particularly high in those aged 20–35. The only comparable disease to this was the Black Death, or bubonic plague, in the 1300s. As other studies have shown, tuberculosis and influenza had comorbidities and one affected the other. The ages of males dying of the flu show that tuberculosis was a factor, and as males primarily had this disease at the time of the pandemic, they had a higher mortality rate. Life expectancy dropped in males during the pandemic but then increased two years after the pandemic.[373]

Island of Newfoundland

One major cause of the spread of influenza was social behavior. Men had more social variation and were mobile more than women due to their work. Even though there was a higher mortality rate in males, each region showed different results, due to such factors as nutritional deficiency. In Newfoundland, the pandemic spread was highly variable. Influenza did not discriminate who was infected, indeed it attacked the socioeconomic status of people. Although social variability allowed the disease to move quickly geographically, it tended to spread faster and affect men more than women due to labor and social contact. Newfoundland's leading cause of death before the pandemic was tuberculosis and this is known to be a severe underlying condition for people and increases the |mortality rate when infected by the influenza disease. There was diverse labor in Newfoundland, men and women had various occupations that involved day-to-day interaction. But, fishing had a major role in the economy and so males were more mobile than females and had more contact with other parts of the world. The spread of the pandemic is known to have begun in the spring of 1918, but Newfoundland didn't see the deadly wave until June or July, which aligns with the high demand for employment in the fishery. The majority of men were working along the coast during the summer and it was typical for entire families to move to Newfoundland and work. Studies show a much higher mortality rate in males compared with females. But, during the first, second, and third waves of the pandemic, the mortality shifted. During the first wave, men had a higher mortality rate, but the mortality rate of females increased and was higher during the second and third waves. The female population was larger in certain regions of Newfoundland and therefore had a bigger impact on the death rate.[374]

Influenza pandemic among Canadian soldiers

Records indicate the most deaths during the first wave of the pandemic were among young men in their 20s, which reflects the age of enlistment in the war. The mobility of young men during 1918 was linked to the spread of influenza and the biggest wave of the epidemic. In late 1917 and throughout 1918, thousands of male troops gathered at the Halifax port before heading to Europe. Any soldier that was ill and could not depart was added to the population of Halifax, which increased the case rate of influenza among men during the war. To determine the cause of the death during the pandemic, war scientists used the Commonwealth War Graves Commission (CWGC), which reported under 2 million men and women died during the wars, with a record of those who died from 1917 to 1918. The movement of soldiers during this time and the transportation from United States between Canada likely had a significant effect on the spread of the pandemic.[375]

See also


  1. The Israelites asked: "Ma'n Hu?" {?מן הוא} – English for 'what is it?'[20]
  2. Then paying in Madrid,The Song of Forgetting (La canción del olvido)—because the tune was as catchy as the flu.[63]



  1. 1.0 1.1 1.2 Yang W, Petkova E, Shaman J (March 2014). "The 1918 influenza pandemic in New York City: age-specific timing, mortality, and transmission dynamics". Influenza and Other Respiratory Viruses. National Institutes of Health. 8 (2): 177–88. doi:10.1111/irv.12217. PMC 4082668. PMID 24299150.
  2. 2.0 2.1 2.2 2.3 2.4 Taubenberger & Morens 2006.
  3. "Pandemic Influenza Risk Management WHO Interim Guidance" (PDF). World Health Organization. 2013. p. 25. Archived (PDF) from the original on 21 January 2021. Retrieved 21 August 2021.
  4. 4.0 4.1 4.2 4.3 4.4 Spreeuwenberg P, Kroneman M, Paget J (December 2018). "Reassessing the Global Mortality Burden of the 1918 Influenza Pandemic". American Journal of Epidemiology. Oxford University Press. 187 (12): 2561–67. doi:10.1093/aje/kwy191. PMC 7314216. PMID 30202996.
  5. Rosenwald MS (7 April 2020). "History's deadliest pandemics, from ancient Rome to modern America". The Washington Post. Archived from the original on 7 April 2020. Retrieved 11 April 2020.
  6. Hale, Tom (10 May 2022). "Flu Strains Descended From 1918 "Spanish Flu" Pandemic Still Linger Today, New Study Suggests". IFLSCIENCE. Archived from the original on 16 January 2023. Retrieved 7 January 2023.
  7. CDC (17 December 2019). "The Discovery and Reconstruction of the 1918 Pandemic Virus". Centers for Disease Control and Prevention. Archived from the original on 25 March 2020. Retrieved 19 September 2022.
  8. 8.0 8.1 Mayer J (29 January 2019). "The Origin Of The Name 'Spanish Flu'". Science Friday. Archived from the original on 29 January 2019. Retrieved 30 July 2021. Etymology: In ancient times, before epidemiology science, people believed the stars and “heavenly bodies” flowed into us and dictated our lives and health—influenza means 'to influence' in Italian, and the word stems from the Latin for 'flow in.' Sickness, like other unexplainable events, was attributed to the influence of the stars... But the name for the infamous 1918 outbreak, the Spanish flu, is actually a misnomer.
  9. Gagnon, Miller & et al 2013, p. e69586.
  10. 10.0 10.1 More AF, Loveluck CP, Clifford H, Handley MJ, Korotkikh EV, Kurbatov AV, et al. (September 2020). "The Impact of a Six-Year Climate Anomaly on the "Spanish Flu" Pandemic and WWI". GeoHealth. 4 (9): e2020GH000277. doi:10.1029/2020GH000277. PMC 7513628. PMID 33005839.
  11. 11.0 11.1 11.2 11.3 11.4 11.5 11.6 Barry 2004b.
  12. MacCallum WG (1919). "Pathology of the pneumonia following influenza". Journal of the American Medical Association. 72 (10): 720–23. doi:10.1001/jama.1919.02610100028012. Archived from the original on 25 January 2020. Retrieved 16 August 2019.
  13. Hirsch EF, McKinney M (1919). "An epidemic of pneumococcus broncho-pneumonia". The Journal of Infectious Diseases. 24 (6): 594–617. doi:10.1093/infdis/24.6.594. JSTOR 30080493. Archived from the original on 24 July 2020. Retrieved 24 May 2020.
  14. Brundage JF, Shanks GD (December 2007). "What really happened during the 1918 influenza pandemic? The importance of bacterial secondary infections". The Journal of Infectious Diseases. 196 (11): 1717–18, author reply 1718–19. doi:10.1086/522355. PMID 18008258.
  15. Morens DM, Fauci AS (April 2007). "The 1918 influenza pandemic: insights for the 21st century". The Journal of Infectious Diseases. 195 (7): 1018–28. doi:10.1086/511989. PMID 17330793.
  16. 16.0 16.1 "Influenza Pandemic Plan. The Role of WHO and Guidelines for National and Regional Planning" (PDF). World Health Organization. April 1999. pp. 38, 41. Archived (PDF) from the original on 3 December 2020.
  17. Michaelis M, Doerr HW, Cinatl J (August 2009). "Novel swine-origin influenza A virus in humans: another pandemic knocking at the door". Medical Microbiology and Immunology. 198 (3): 175–83. doi:10.1007/s00430-009-0118-5. PMID 19543913. S2CID 20496301. Archived from the original on 15 May 2021. Retrieved 26 July 2021.
  18. Mermel LA (June 2009). "Swine-origin influenza virus in young age groups". Lancet. 373 (9681): 2108–09. doi:10.1016/S0140-6736(09)61145-4. PMID 19541030. S2CID 27656702. Archived from the original on 27 July 2021. Retrieved 5 April 2021.
  19. Davis 2013, p. 7: "In short, although the Spanish flu 'had nothing "Spanish" about it,' from a strictly epidemiological perspective, its discursive link to the Iberian nation is beyond dispute. The importance of narrative for a historically informed appreciation of the epidemic stems from the importance of this discursive link and is tied directly to the scientific uncertainty about the etiological agent of the epidemic;"
  20. "Biblical Hebrew Words and Meaning". hebrewversity. 14 March 2018. Retrieved 11 August 2021. in the original Hebrew the people of Israel asked: "Ma'n Hu?" {?מן הוא} – English for 'what is it?' and that is the origin of the name 'manna'
  21. Spinney 2018, p. 65: "In Freetown, a newspaper suggested that the disease be called manhu until more was known about it. Manhu, a Hebrew word meaning 'what is it?'
  22. Cole F (1994), Sierra Leone and World War 1, University of London, School of Oriental and African Studies, p. 213, 10731720, archived from the original on 11 August 2021, retrieved 11 August 2021 – via ProQuest Dissertations Publishing, local interpretations of the crisis had become deeply reminiscent of the increasing disobedience of the Israelites in the wilderness of Sin. It was therefore urged that the epidemic be called 'Man hu,' (an obvious corruption of "manna") meaning 'what is it?'
  23. Sierra Leone Weekly News, vol. XXXV, 9 July 1918, p. 6 quoted in Mueller JW (1998), p. 8.
  24. Hammond JA, Rolland W, Shore TH (14 July 1917). "Purulent Bronchitis". The Lancet. 190 (4898): 41–46. doi:10.1016/s0140-6736(01)56229-7. ISSN 0140-6736. Archived from the original on 22 March 2023. Retrieved 20 March 2023. Alt URL Archived 26 August 2019 at the Wayback Machine
  25. Radusin M (September 2012). "The Spanish flu--Part I: the first wave". Vojnosanitetski Pregled. 69 (9): 812–817. ISSN 0042-8450. PMID 23050410. Archived from the original on 8 November 2022. Retrieved 20 March 2023. the Purple Death … name resulted from the specific skin colour in the most severe cases of the diseased, who by the rule also succumbed to the disease, and is also at the same time the only one which does not link this disease with the Iberian peninsula. This name is actually the most correct.
  26. McCord CP (8 November 1966). "The Purple Death. Some things remembered about the influenza epidemic of 1918 at one army camp". Journal of Occupational Medicine. Industrial Medical Association. 8 (11): 593–598. ISSN 0096-1736. PMID 5334191. Archived from the original on 8 November 2022. Retrieved 20 March 2023.
  27. Getz D (19 September 2017). Purple death : the mysterious Spanish flu of 1918. ISBN 978-1-250-13909-2. OCLC 1006711971. Archived from the original on 22 March 2023. Retrieved 20 March 2023.
  28. 28.0 28.1 Oxford JS, Gill D (2 September 2019). "A possible European origin of the Spanish influenza and the first attempts to reduce mortality to combat superinfecting bacteria: an opinion from a virologist and a military historian". Human Vaccines & Immunotherapeutics. 15 (9): 2009–2012. doi:10.1080/21645515.2019.1607711. ISSN 2164-5515. PMC 6773402. PMID 31121112. Two papers were published in The Lancet in 1917 describing an outbreak of disease constituting 'almost a small epidemic'. The first paper was written by physicians at a hospital center in northern France,3 and the second by a team at an army hospital in Aldershot, in southern England. In both earlier instances and in the 1918 pandemic the disease was characterized by a 'dusky' cyanosis, a rapid progression from quite minor symptoms to death
  29. 29.0 29.1 Cox J, Gill D, Cox F, Worobey M (1 April 2019). "Purulent bronchitis in 1917 and pandemic influenza in 1918". The Lancet Infectious Diseases. 19 (4): 360–361. doi:10.1016/s1473-3099(19)30114-8. ISSN 1473-3099. PMID 30938298. S2CID 91189842.
  30. Honigsbaum M (23 June 2018). "Spanish influenza redux: revisiting the mother of all pandemics". The Lancet. 391 (10139): 2492–2495. doi:10.1016/S0140-6736(18)31360-6. PMID 29976462. S2CID 49709093. Archived from the original on 6 December 2022. Retrieved 20 March 2023. Labelled 'purulent bronchitis' for want of a better term, the disease proved fatal in half the cases and many soldiers also developed cyanosis. 2 years later, British respiratory experts, also writing in The Lancet, but this time in the wake of the pandemic, would decide the disease had been 'fundamentally the same condition' as 'Spanish' influenza
  31. Shanks GD, MacKenzie A, Waller M, Brundage JF (27 November 2011). "Relationship between 'purulent bronchitis' in military populations in Europe prior to 1918 and the 1918-1919 influenza pandemic: Precursors of pandemic influenza". Influenza and Other Respiratory Viruses. 6 (4): 235–239. doi:10.1111/j.1750-2659.2011.00309.x. PMC 5779808. PMID 22118532.
  32. Storey, C (21 September 2020). "OLD NEWS: Influenza was an old foe long before 1918". Arkansas Democrat-Gazette. Opinion. Archived from the original on 7 August 2021. Retrieved 7 August 2021. I came across this seemingly astute analysis in the Dec. 21, 1913, Gazette.... It was a 'Special Cable to the Gazette Through the International News Service.' Grip Is a Disease Without a Country; All Nations Repudiate Malady: Each Blaming Other Kingdoms, London, Dec. 20. — The grip is a disease without a country, according to a new book just issued which is devoted to the malady. Every country tries to make it out a native of another land.... Eighteenth-century Italian writers say Dr. Hopkirk spoke of "una influenza di freddo" (influence of cold), and English physicians, mistaking the word influenza for the name of the disease itself, used it. The same term is also used in Germany, where a host of dialect names still prevail, such as lightning catarrh and fog plague.
  33. "Grippe is not new". Los Angeles Herald. 14 January 1899. p. 6 col. 6. Archived from the original on 7 August 2021. Retrieved 7 August 2021 – via California Digital Newspaper Collection. French doctors gave it the name of "la grippe," which is now anglicized into "the grip" ... It is known all over the world, and there is a disposition in every nation to shift the odium of it upon some other country. Then the Russians call it the Chinese catarrh, the Germans often call it the Russian pest, the Italians name it the German disease, and the French call it sometimes the Italian fever and sometimes the Spanish catarrh.
  34. Davis 2013, p. 27: "On May 21, 1918, El Liberal published a scant article titled 'Can One Live? The Fashionable Illness.' Likely the first account in Spain of the Spanish flu, it begins: 'For several days, Madrid has been affected by an epidemic, which fortunately is mild; but which, from what it appears, intends to kill doctors from overwork'.... The following day, El Sol and ABC published their first stories about the epidemic: 'What is the Cause? An Epidemic in Madrid' and 'Benign Epidemic. The Sickbay in Madrid,' respectively."
  35. Alfeirán X (7 December 2015). "La fiebre de los tres días" [The three-day fever]. La Voz de Galicia (in español). A Coruña. Archived from the original on 29 July 2021. Retrieved 29 July 2021. Las primeras noticias aparecieron en la prensa de Madrid el 21 de mayo de 1918. [The first news appeared in the press of Madrid on 21 May 1918.]
  36. McClure J (1 May 2009). "Spanish flu of 1918 no three-day fever. Try 365-day worldwide plague". York Daily Record. Archived from the original on 29 July 2021. Retrieved 29 July 2021.
  37. Calleja S (29 July 2021). "La fiebre de los tres días" [The three-day fever]. Diario de León (in español). León, Spain. Archived from the original on 29 July 2021. Retrieved 21 October 2018.
  38. "Impacto de la gripe de 1918 en España". Comité Asesor de Vacunas de la Asociación Española de Pediatría [Vaccine Advisory Committee of the Spanish Association of Pediatrics] (in español). Archived from the original on 29 July 2021. Retrieved 29 July 2021. En España, se le llamó al principio 'la fiebre de los tres días', atendiendo a la creencia, como en otros países, de que la gripe era una enfermedad leve. Las primeras noticias sobre la gripe, llamando la atención sobre que algo distinto estaba ocurriendo, aparecieron en la prensa a finales de mayo. Por ej. en el diario ABC el 22 de mayo mediante una escueta nota en la página 24: 'Los médicos han comprobado, en Madrid, la existencia de una epidemia de índole gripal, muy propagada, pero, por fortuna, de carácter leve'. [In Spain, it was initially called 'the three-day fever', based on the belief, as in other countries, that the flu was a mild illness. The first reports about the flu, drawing attention to the fact that something different was happening, appeared in the press at the end of May. For example, in the newspaper ABC on 22 May, through a brief note on page 24: "The doctors have verified, in Madrid, the existence of an epidemic of a influenza nature, very widespread, but, fortunately, of a mild nature.']
  39. Killingray D, Phillips H (2 September 2003). The Spanish Influenza Pandemic of 1918-1919: New Perspectives. Routledge. ISBN 978-1-134-56640-2. Archived from the original on 22 March 2023. Retrieved 20 March 2023. In the popular mind calamities often need to have their origin and cause identified and other countries or peoples credited with blame. This xenophobic response has been common in Europe, that impulse to blame others or the silent places of the Asian heartlands for the source of disease.
  40. 40.0 40.1 Hoppe T (November 2018). ""Spanish Flu": When Infectious Disease Names Blur Origins and Stigmatize Those Infected". American Journal of Public Health. 108 (11): 1462–1464. doi:10.2105/AJPH.2018.304645. PMC 6187801. PMID 30252513.
  41. 41.0 41.1 41.2 Bax D (2020). "Pandemie – Welt im Fieber" [Pandemic - World in Fever]. (in Deutsch) (13). Archived from the original on 31 July 2021. Retrieved 31 July 2021. In Großbritannien wurde die Krankheit dagegen als 'Flandrische Grippe' bezeichnet, weil sich viele —en in den Schützengräben von Flandern ansteckten. [In Britain, on the other hand, the disease was called the 'Flanders flu' because many soldiers became infected in the trenches of Flanders.]
  42. Reynolds JR (1866). A System of Medicine. Vol. 1. Macmillan. pp. 30–31. Archived from the original on 22 March 2023. Retrieved 20 March 2023. One is, that every epidemic owns one unknown source, whence it spreads; each nation, in turn, attributing to its neighbour from whom it derived the disease, the unenviable honour of originating it. Thus the Italians have termed it the German disease; the Germans, the Russian pest; the Russians, the Chinese Catarrh;
  43. Harrison MA, Claiborne JH Jr, eds. (January 1890). "Editorials: La Grippe". Gaillard's Medical Journal. 50: 217. Archived from the original on 22 March 2023. Retrieved 20 March 2023. The outbreak immediately preceding the present one was in 1879, and has been well described by Da Costa. Like every other disease about whose pathology we know very little, this malady has not a scientifically correct name, but at different times and in different countries has received names which are almost purely local; thus the Russians have called it the Chinese catarrh, because it has often invaded Russia from China. The Germans call it the Russian pest, while the Italians in turn call it the German disease.
  44. 44.0 44.1 44.2 Davis KC (2018). More deadly than war : the hidden history of the Spanish flu and the First World War (First ed.). New York. ISBN 978-1-250-14512-3. OCLC 1034984776. The Russians called it the Chinese flu. In Japan, it was wrestler's fever. In South Africa, it was known as either the white man's sickness or kaffersiekte blacks' disease. Soldiers fighting in the Great War called it the three-day fever—a highly inaccurate description—and when it first struck in the spring of 1918, German soldiers called it Flanders fever, after one of the war's most notorious and deadly battlefields
  45. Porras-Gallo & Davis 2014, p. 51.
  46. Galvin 2007.
  47. Own Correspondent (2 June 1918). "The Spanish Epidemic". The Times. London. Archived from the original on 29 July 2021. Retrieved 29 July 2021. The unknown disease which appeared in Madrid a fortnight ago spread with remarkable rapidity.... It is reported that there are well over 100,000 victims in Madrid alone.... Although the disease is clearly of a gripal character...
  48. "The Spanish Influenza; A Sufferer's Symptoms". The Times. London. 25 June 1918. Archived from the original on 29 July 2021. Retrieved 29 July 2021.
  49. "Public Notice; 'Spanish Influenza' Epidemic". The Times. London. 28 June 1918. Archived from the original on 12 August 2021. Retrieved 11 August 2021.
  50. Arnold C (13 September 2018). "Eat More Onions!". Lapham's Quarterly. Archived from the original on 12 August 2021. Retrieved 12 August 2021. daily newspapers carried an increasing number of advertisements for influenza-related remedies as drug companies played on the anxieties of readers and reaped the benefits. From the Times of London to the Washington Post, page after page was filled with dozens of advertisements for preventive measures and over-the-counter remedies. 'Influenza!' proclaimed an advert extolling the virtues of Formamint lozenges.
  51. Daniels R (29 April 2018) [1998 Mill Hill Essays]. "In Search of an Enigma: The "Spanish Lady"". NIMR History. Archived from the original on 29 April 2018. Retrieved 9 August 2021 – via In turn, when Russia reported on the situation in Moscow, Pravda printed "Ispanka (The Spanish Lady) is in town" and the name has stuck.
  52. 52.0 52.1 Trilla A, Trilla G, Daer C (September 2008). "The 1918 "Spanish flu" in Spain". Clinical Infectious Diseases. 47 (5): 668–73. doi:10.1086/590567. PMID 18652556.
  53. "Spanish flu facts". Channel 4 News. Archived from the original on 27 January 2010.
  54. Anderson S (29 August 2006). "Analysis of Spanish flu cases in 1918–1920 suggests transfusions might help in bird flu pandemic". American College of Physicians. Archived from the original on 25 November 2011. Retrieved 2 October 2011.
  55. Barry 2004, p. 171.
  56. Spinney L (29 September 2018). "The centenary of the 20th century's worst catastrophe". The Economist. Science & technology. ISSN 0013-0613. Archived from the original on 3 August 2021. Retrieved 3 August 2021. On June 29th 1918 Martín Salazar, Spain's inspector-general of health, stood up in front of the Royal Academy of Medicine in Madrid. He declared, not without embarrassment, that the disease which was ravaging his country was to be found nowhere else in Europe. In fact, that was not true. The illness in question, influenza, had been sowing misery in France and Britain for weeks, and in America for longer, but Salazar did not know this because the governments of those countries, a group then at war with Germany and its allies, had made strenuous efforts to suppress such potentially morale-damaging news.{{cite news}}: CS1 maint: date and year (link)
  57. "Madrid Letter". Journal of the American Medical Association. 71 (19): 1594. 9 November 1918. Archived from the original on 22 March 2023. Retrieved 20 March 2023.
  58. Radusin M (September 2012). "The Spanish flu – Part I: the first wave". Vojnosanitetski Pregled. 69 (9): 812–817. ISSN 0042-8450. PMID 23050410. Archived from the original on 8 November 2022. Retrieved 20 March 2023. 'The Serbian Newspaper' wrote in the period October 23 / November 5, 1918 at the peak of the second, deadliest wave of the pandemic: 'Various countries have been assigning the origin of this imposing guest to each other for quite some time, and at one point in time they agreed to assign its origin to the kind and neutral Spain, which had been fighting off this honour just as much as German submarines, so imposing in their search for hospitality off Spanish shores.'
  59. 59.0 59.1 59.2 Vázquez-Espinosa E, Laganà C, Vázquez F (October 2020). "The Spanish flu and the fiction literature". Revista Espanola de Quimioterapia. 33 (5): 296–312. doi:10.37201/req/049.2020. PMC 7528412. PMID 32633114. Archived from the original on 10 February 2023. Retrieved 20 March 2023. French journalists had, initially, called it the 'American flu'; but the fact that the American soldiers were his allies in the warlike conflict advised not to assign such a link to them.... Another most popular name in Madrid, was the 'Soldado de Nápoles' (Naples soldier), a popular song in the zarzuela (popular musical genre or 'género chico' in Spain) called La canción del olvido (The forgotten song) due both, were 'highly contagious'. Today, there are many authors who avoid such a name (the Spanish flu) and they aptly refer to it as the '1918- 1819[sic] influenza pandemic'
  60. Müller S (2020). "Spanische Grippe" [The Spanish Flu]. (in Deutsch). Bonn: Friedrich Ebert Foundation. Archived from the original on 31 July 2021. Retrieved 31 July 2021. In Europa wurde die Spanischer Grippe auch als 'Blitzkatarrh', als 'Flandern-Fieber', 'flandische Grippe', bei Engländern und Amerikanern als 'three-day'- oder 'knock-me-down'-Fieber, und in Frankreich als 'la grippe', als 'bronchite purulente' (eitrige Bronchitis) oder beim französische Militärärzte als 'Krankheit 11' (maladie onze) bezeichnet. Die Benennung von Krankheiten und insbesondere Seuchen nach ihrem vermuteten Ursprungsort ist nichts Ungewöhnliches. Es ist der Versuch, einem Geschehen auf die Spur zu kommen. Zugleich werden auf diese Weise Krankheiten als etwas Äußerliches gekennzeichnet, als etwas Fremdes, das eingedrungen ist oder eingeschleppt wurde. [In Europe, the Spanish flu was also referred to as 'Blitzkatarrh', as 'Flanders fever', 'Flanders flu', in English and Americans as 'three-day' or 'knock-me-down' fever, and in France as 'la flu', as 'bronchite purulente' (purulent bronchitis) or by French military doctors as 'disease 11' (maladie onze). The naming of diseases and especially epidemics according to their presumed place of origin is nothing unusual. It is an attempt to track down what is happening. At the same time, in this way, diseases are marked as something external, as something foreign that has invaded or been introduced.]
  61. 61.0 61.1 Cotter C (23 April 2020). "From the 'Spanish Flu' to COVID-19: lessons from the 1918 pandemic and First World War". Humanitarian Law & Policy. International Committee of the Red Cross. Archived from the original on 7 August 2021. Retrieved 7 August 2021. Many other nicknames were given to the pandemic, many based on nationality or race: 'Spanish Lady', 'French Flu', 'Naples Soldier', 'Purple Death', 'War Plague', 'Flanders Grippe', 'Kirghiz Disease', 'Black Man's Disease', 'Hun Flu', 'German Plague', 'Bolshevik Disease' or even the 'Turco-Germanic bacterium criminal entreprise'. These discriminatory epithets reflect the many rumors and theories that quickly spread about the origins of the pathology.
  62. 62.0 62.1 Spinney 2018, p. 58.
  63. Davis 2013, pp. 103–36.
  64. Landgrebe P (29 December 2018). "100 Years After: The Name of Death". History Campus. Archived from the original on 16 August 2020. Retrieved 16 August 2020.
  65. Rodríguez LP, Palomba AL (5 March 2019). "How is the adjective 'Spanish' used in other languages?". El País (English ed.). Madrid. Archived from the original on 1 August 2021. Retrieved 1 August 2021. The use of 'Spanish' can often have negative connotations, with the adjective often unfairly used to describe unwelcome events and problems. The most obvious example is the so-called 'Spanish flu,' a reference to the 1918 influenza pandemic...
  66. O'Reilly T (13 May 2020). "How the Spanish Flu wasn't Spanish at all". CBC Radio. Under the Influence. Archived from the original on 1 August 2021. Retrieved 1 August 2021. Medical professionals and officials in Spain protested. They said the Spanish people were being falsely stigmatized.... If you've ever wondered about the staying power of a brand, the 'Spanish Flu' is a case in point. A full 100 years later, the 'Spanish Flu' is still referenced — and still remains a source of irritation in Spain.
  67. Takon L (7 April 2020). "Fighting words: how war metaphors can trigger racism". The Lighthouse. Macquarie University. Archived from the original on 8 August 2021. Retrieved 8 August 2021. the names given to this disease in different parts of the world reflected prevailing concerns about certain ethnic groups and ideologies. The disease was called the 'Singapore fever' in Penang and the Bolshevik disease in Poland.
  68. Phillips, H. (1990). Black October: The Impact of the Spanish Influenza Epidemic of 1918 on South Africa. Government Printer, South Africa. ISBN 978-0-7970-1580-7. Archived from the original on 22 March 2023. Retrieved 20 March 2023. In one area where Blacks were the first victims, the accusatory term 'Kaffersiekte' was coined; in another district, where the position was reversed, Blacks returned the compliment with, White man's sickness'
  69. 余録:「春のさきぶれ」といえば何か聞こえが良いが… [Speaking of "spring sekibu", something sounds good...]. =毎日新聞 [Mainichi Shimbun morning newspaper] (in 日本語). 15 May 2020. Archived from the original on 8 August 2021. Retrieved 8 August 2021. 翌月の東京の夏場所は高熱などによる全休力士が相次いだ。世間はこれを「相撲風邪」「力士風邪」と呼んだが、実はこの謎の感染症こそが同年初めから米国で流行の始まった「スペイン風邪」とみられている。 [The following month, a number of sumo wrestlers were absent from the summer tournament in Tokyo due to high fevers. People called it the "sumo flu" or "wrestler flu," but in fact, this mysterious infection is believed to be the Spanish flu, which began spreading in the United States early that year.]
  70. "How the Spanish flu of 1918-20 ravaged Japan". Japan Today. Archived from the original on 8 August 2021. Retrieved 8 August 2021. The first patients in Japan, reported Shukan Gendai (May 2–9), began showing symptoms around April 1918. Initially the disease was referred to as the "Sumo Kaze" (sumo cold) because a contingent of sumo wrestlers contracted it while on a tour of Taiwan. Three well known grapplers, Masagoishi, Choshunada and Wakagiyama, died before they could return from Taiwan. As the contagion spread, the summer sumo tournament, which would have been held on the grounds of Yasukuni shrine, was cancelled.
  71. Dionne & Turkmen 2020, pp. 213–230.
  72. "WHO issues best practices for naming new human infectious diseases". 8 May 2015. Archived from the original on 31 July 2021. Retrieved 4 August 2021.
  73. "Pandemic influenza: an evolving challenge". World Health Organization. 22 May 2018. Archived from the original on 20 March 2020. Retrieved 20 March 2020.
  74. "Influenza pandemic of 1918–19". Encyclopaedia Britannica. 4 March 2020. Archived from the original on 20 March 2020. Retrieved 20 March 2020.
  75. Chodosh S (18 March 2020). "What the 1918 flu pandemic can teach us about COVID-19, in four charts". PopSci. Archived from the original on 24 December 2020. Retrieved 20 March 2020.
  76. Mueller JW (1998). What's in a name. Spanish Influenza in sub-Saharan Africa and what local names say about the perception of this pandemic. Spanish 'Flu 1918–1998: Reflections on the Influenza Pandemic of 1918 after 80 Years. Cape Town, South Africa. Archived from the original on 30 November 2021. Retrieved 13 August 2021.
  77. Phillips H (8 October 2014). "Influenza Pandemic (Africa)". International Encyclopedia of the First World War (WW1). Archived from the original on 13 August 2021. Retrieved 13 August 2021.
  78. Great Britain Ministry of Health (1920). Report on the Pandemic of Influenza, 1918–19. H.M. Stationery Office. Archived from the original on 22 March 2023. Retrieved 20 March 2023. There was a high west wind at the time and this was thought to be the carrying agent so that the affliction was called 'the disease of the wind.'
  79. Afkhami AA (5 February 2019). A Modern Contagion: Imperialism and Public Health in Iran's Age of Cholera. JHU Press. ISBN 978-1-4214-2722-5. Archived from the original on 22 March 2023. Retrieved 20 March 2023. In Tehran, the disease was called the "illness of the wind" (nakhushi-yi bad) due to its initial occurrence during a strong westerly wind burst and its rapid spread.
  80. Archives of Internal Medicine. Vol. 24. Chicago: American Medical Association. 1919. Archived from the original on 22 March 2023. Retrieved 20 March 2023. As this included the period of the great influenza epidemic when Type IV infections were usually prevalent, it will be seen that the proportion of fixed types among carriers and among cases is not far from the same.
  81. United States Surgeon-General's Office (1920). Report of the Surgeon-General of the Army to the Secretary of War for the Fiscal Year Ending June 30, 1919. War Department Annual Reports. Vol. I. U.S. Government Printing Office. Archived from the original on 22 March 2023. Retrieved 20 March 2023. On September 13, 1918, the first cases of the great influenza epidemic were admitted, and during the next 10 weeks over 4,100 patients were admitted.
  82. Spinney 2018, p. 64: "In … Rhodesia (Zimbabwe) … officials labelled the new affliction 'influenza (vera)', adding the Latin word vera, meaning 'true' … German doctors … called it 'pseudo-influenza'"
  83. Cross A (29 March 2020). "A look at art and music created in times of pandemic". Global News (Canada). Archived from the original on 10 August 2021. Retrieved 9 August 2021. Another rhyme with deadly origins appeared during a worldwide influenza pandemic in 1889-1890. Certain the disease could be stopped by sealing up the home from the poisoned air outside, this safety tip emerged in schools: There was a little girl, and she had a little bird; And she called it by the pretty name of Enza; But one day it flew away, but it didn't go to stay; For when she raised the window, in-flu-Enza
  84. University Libraries. "WWI Exhibit: Influenza Pandemic". University of Washington. Archived from the original on 9 August 2021. Retrieved 9 August 2021.
  85. Hakim J (September 2002). War, Peace, and All that Jazz. Oxford University Press. ISBN 978-0-19-515335-4. Archived from the original on 22 March 2023. Retrieved 20 March 2023. In flew Enza—say it fast and it becomes 'influenza.' It was a catchy little rhyme, and boys and girls skipped rope to it.
  86. Honigsbaum M (18 October 2016). Living with Enza: The Forgotten Story of Britain and the Great Flu Pandemic of 1918. Springer. ISBN 978-0-230-23921-0. Archived from the original on 22 March 2023. Retrieved 20 March 2023. A popular playground skipping rhyme caught the ease with which this 'new disease' was transmitted: I had a little bird; Its name was Enza; I opened the window; And in-flu-enza. As influenza spread from Glasgow to Aberdeen, and from Liverpool to London's Mile End, it was not long before playgrounds throughout the country echoed to the chant.
  87. March PC (4 September 1932). "General March's Narrative: Glimpses of Woodrow Wilson". The New York Times. p. XX3, Special Features section. Archived from the original on 10 August 2021. Retrieved 20 March 2023.
  88. "The 1918 Flu Pandemic Killed Hundreds of Thousands of Americans. The White House Never Said a Word About It". Time. Archived from the original on 10 August 2021. Retrieved 10 August 2021. Crosby's America's Forgotten Pandemic: The Influenza of 1918, Wilson asked Army Chief of Staff General Peyton March in October 1918 if he had heard of the popular jump rope rhyme parodying the virus, and recited part of it.
  89. 89.0 89.1 89.2 Spinney 2018, p. 36.
  90. "1918 Flu (Spanish flu epidemic)". Avian Bird Flu. Archived from the original on 21 May 2008.
  91. Sheidlower N (17 March 2020). "How NYC Survived the 1918 Spanish Flu Pandemic". Untapped New York. Archived from the original on 29 September 2020. Retrieved 8 October 2020.
  92. Billings 1997.
  93. "The Memoirs of Herbert Hoover: Years of Adventure, 1874–1920. (New York: Macmillan Company. 1951. pp. xi, 496.) and Herbert Hoover and the Russian Prisoners of World War I: A Study in Diplomacy and Relief, 1918–1919. By Edward F. Willis. (Stanford: Stanford University Press. 1951. pp. viii, 67.)". The American Historical Review: 12. 2011. doi:10.1086/ahr/57.3.709. ISSN 1937-5239.
  94. 94.0 94.1 Spinney 2018, p. 37.
  95. "Queer Epidemic Sweeps North China; Banks and Silk Stores in Peking Closed – Another Loan Sought from Japan". The New York Times. 1 June 1918. ISSN 0362-4331. Archived from the original on 24 June 2020. Retrieved 22 June 2020.
  96. 96.0 96.1 96.2 96.3 96.4 96.5 96.6 Patterson & Pyle 1991.
  97. 97.0 97.1 "Mortality Statistics 1918: Nineteenth Annual Report" (PDF). United States Census Bureau. 1920. p. 28. Archived (PDF) from the original on 11 July 2020. Retrieved 29 May 2020.
  98. Erkoreka A (March 2010). "The Spanish influenza pandemic in occidental Europe (1918–1920) and victim age". Influenza and Other Respiratory Viruses. 4 (2): 81–89. doi:10.1111/j.1750-2659.2009.00125.x. PMC 5779284. PMID 20167048.
  99. 99.0 99.1 Spinney 2018, p. 38.
  100. Byerly CR (April 2010). "The U.S. military and the influenza pandemic of 1918–1919". Public Health Reports. 125 (Suppl 3): 82–91. doi:10.1177/00333549101250S311. PMC 2862337. PMID 20568570.
  101. 101.0 101.1 Spinney 2018, p. 39.
  102. 102.0 102.1 "Atatürk işgalcilerden önce İspanyol Gribini yenmişti". (in Türkçe). Archived from the original on 8 November 2020. Retrieved 2 November 2020.
  103. Spinney 2018, p. 40.
  104. Barry JM (2005). The Great Influenza. United States: Penguin Books. p. 270. ISBN 0-670-89473-7. On September 15, New York City's first influenza death occurred.
  105. Flynn M (12 March 2020). "What happens if parades aren't canceled during pandemics? Philadelphia found out in 1918, with disastrous results". The Washington Post. Archived from the original on 4 July 2020. Retrieved 9 July 2020.
  106. Spinney 2018, p. 41.
  107. Spinney 2018, p. 42.
  108. Kenner R (18 January 2010). "Influenza 1918". American Experience. Season 10. Episode 5. PBS. WGBH. Archived from the original on 27 May 2020. Transcript. Retrieved 27 May 2020.
  109. "Epidemic Influenza". p. 93. Archived from the original on 4 July 2020. Retrieved 4 July 2020.
  110. 110.0 110.1 110.2 110.3 Chandra, S.; Christensen, J.; Likhtman, S. (6 November 2020). "Connectivity and seasonality: the 1918 influenza and COVID-19 pandemics in global perspective". Journal of Global History. 15 (3): 408–420. doi:10.1017/S1740022820000261. Archived from the original on 12 July 2022. Retrieved 20 March 2023 – via CambridgeCore.
  111. 111.0 111.1 Bootsma, M. C. J.; Ferguson, N. M. (1 May 2007). "The effect of public health measures on the 1918 influenza pandemic in U.S. cities". Proceedings of the National Academy of Sciences of the United States of America. 104 (18): 7588–7593. doi:10.1073/pnas.0611071104. PMC 1849868. PMID 17416677. Archived from the original on 17 March 2023. Retrieved 20 March 2023 – via PNAS.
  112. "Weekly Reports for NOVEMBER 29, 1918". Public Health Reports. 33 (48): 2093. 29 November 1918. PMC 1999834. PMID 19314645. Archived from the original on 26 November 2022. Retrieved 20 March 2023 – via PubMed Central.
  113. 113.0 113.1 "Weekly Reports for December 6, 1918". Public Health Reports. 33 (49): 2153. 6 December 1918. PMC 1999845. PMID 19314646. Archived from the original on 21 March 2023. Retrieved 20 March 2023 – via PubMed Central.
  114. Chandra, S.; Christensen, J.; Chandra, M.; Paneth, N. (March 2021). "Pandemic Reemergence and Four Waves of Excess Mortality Coinciding With the 1918 Influenza Pandemic in Michigan: Insights for COVID-19". American Journal of Public Hleath. 111 (3): 435. Archived from the original on 17 March 2023. Retrieved 20 March 2023.
  115. 115.0 115.1 115.2 115.3 115.4 115.5 115.6 Jordan, E. O. (1927). Epidemic Influenza: A Survey. Chicago: American Medical Association. Archived from the original on 17 March 2023. Retrieved 20 March 2023.
  116. "Here are Exact Facts About the Influenza and Its Toll in City, State, Nation, world". Los Angeles Times. 9 February 1919. Archived from the original on 24 July 2020. Retrieved 10 May 2020.
  117. 117.0 117.1 Vaughan, W. T. (July 1921). "Influenza: An Epidemiologic Study". American Journal of Hygiene. ISBN 978-0-598-84038-7. Archived from the original on 24 July 2020.
  118. "Weekly Reports for FEBRUARY 21, 1919". Public Health Reports. 34 (8): 313. 21 February 1919. PMC 1996943. PMID 19314657. Archived from the original on 21 March 2023. Retrieved 20 March 2023 – via PubMed Central.
  119. "Mortality Statistics 1919: Twentieth Annual Report" (PDF). United States Census Bureau. 1921. p. 30. Archived (PDF) from the original on 12 July 2020. Retrieved 11 May 2020.
  120. Pearce, D. C; Pallaghy, P. K.; McCaw, J. M.; McVernon, J.; Mathews, J. D. (2011). "Understanding mortality in the 1918–1919 influenza pandemic in England and Wales". Influenza and Other Respiratory Viruses. 5 (2): 91. Archived from the original on 17 March 2023. Retrieved 20 March 2023.
  121. 121.0 121.1 121.2 121.3 Ansart, S.; Pelat, C.; Boelle, P.-Y.; Carrat, F.; Flahault, A.; Valleron, A.-J. (May 2009). "Mortality burden of the 1918–1919 influenza pandemic in Europe". Influenza and Other Respiratory Viruses. 3 (3): 99–106. doi:10.1111/j.1750-2659.2009.00080.x. PMC 4634693. PMID 19453486. Archived from the original on 17 March 2023. Retrieved 20 March 2023 – via Wiley Online Library.
  122. Chowell, G.; Erkoreka, A.; Viboud, C.; Echeverri-Dávila, B. (2014). "Spatial-temporal excess mortality patterns of the 1918–1919 influenza pandemic in Spain". BMC Infectious Diseases. 14 (371). doi:10.1186/1471-2334-14-371. PMC 4094406. PMID 24996457. Archived from the original on 8 January 2023. Retrieved 20 March 2023.
  123. Nunes, B.; Silva, S.; Rodrigues, A.; Roquette, R.; Batista, I.; Rebelo-de-Andrade, H. (December 2018). "The 1918–1919 Influenza Pandemic in Portugal: A Regional Analysis of Death Impact". American Journal of Epidemiology. 187 (12): 2541–2549. doi:10.1093/aje/kwy164. PMC 7314274. PMID 30099487. Archived from the original on 17 March 2023. Retrieved 20 March 2023 – via Oxford Academic.
  124. 124.0 124.1 124.2 Holbrook, C. (August 2022). "Public Health in a Federation: Lessons from the Spanish Influenza in Australia". Social History of Medicine. 35 (3): 818–846. doi:10.1093/shm/hkac005. PMC 9383459. PMID 36046217. Archived from the original on 26 January 2023. Retrieved 20 March 2023 – via Oxford Academic.
  125. 125.0 125.1 125.2 125.3 Shanks, G. D. "Australia's Experience of the 1918-19 Influenza Pandemic: Lessons Learned" (PDF). University of Otago. Archived (PDF) from the original on 19 September 2020. Retrieved 20 March 2023.
  126. 126.0 126.1 Curson, P.; McCracken, K. (2006). "An Australian perspective of the 1918–1919 influenza pandemic". New South Wales Public Health Bulletin. 17 (8): 103. Archived from the original on 8 October 2022. Retrieved 20 March 2023.
  127. "Weekly Reports for AUGUST 22, 1919". Public Health Reports. 34 (34): 1959. 22 August 1919. PMC 1996930. PMID 19314683. Archived from the original on 21 March 2023. Retrieved 20 March 2023 – via PubMed Central.
  128. Ho, P.-L.; Chow, K.-H. (November 2009). "Mortality burden of the 1918–1920 influenza pandemic in Hong Kong". Influenza and Other Respiratory Viruses. 3 (6): 261–263. doi:10.1111/j.1750-2659.2009.00105.x. PMC 4941390. PMID 19903207 – via Wiley Online Library.
  129. "Weekly Reports for MAY 30, 1919". Public Health Reports. 34 (22): 1232. 30 May 1919. PMC 1996920. PMID 19314671. Archived from the original on 21 March 2023. Retrieved 20 March 2023 – via PubMed Central.
  130. "Weekly Reports for AUGUST 1, 1919". Public Health Reports. 34 (31): 1735. 1 August 1919. PMC 1996928. PMID 19314680 – via PubMed Central.
  131. "Weekly Reports for AUGUST 29, 1919". Public Health Reports. 34 (35): 2003. 29 August 1919. PMC 1996931. PMID 19314684. Archived from the original on 21 March 2023. Retrieved 20 March 2023 – via PubMed Central.
  132. "Weekly Reports for AUGUST 15, 1919". Public Health Reports. 34 (33): 1920. 15 August 1919. PMC 1996932. PMID 19314682. Archived from the original on 13 April 2022. Retrieved 20 March 2023 – via PubMed Central.
  133. 133.0 133.1 133.2 Chowell, G.; Simonsen, L.; Flores, J.; Miller, M. A.; Viboud, C. (November 2014). "Death Patterns during the 1918 Influenza Pandemic in Chile". Emerging Infectious Diseases. 20 (11): 1803–1811. PMC 4214284. PMID 25341056. Archived from the original on 6 February 2023. Retrieved 20 March 2023.
  134. Cristina, J.; Pollero, R.; Pellegrino, A. (May 2019). "The 1918 influenza pandemic in Montevideo: The southernmost capital city in the Americas". Influenza and Other Respiratory Viruses. 13 (3): 219–225. doi:10.1111/irv.12619. PMC 6468140. PMID 30422393. Archived from the original on 17 March 2023. Retrieved 20 March 2023 – via Wiley Online Library.
  135. Najera RF (2 January 2019). "Influenza in 1919 and 100 Years Later". College of Physicians of Philadelphia. Archived from the original on 24 July 2020. Retrieved 23 April 2020.
  136. Frost, W. H. (15 August 1919). "The Epidemiology of Influenza". Public Health Reports. 34 (33): 1823–1926. doi:10.2307/4575271. JSTOR 4575271. PMC 1996932. PMID 19314682.
  137. "WARNS OF INFLUENZA". The New York Times. 15 August 1919. p. 6. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  138. "AT ISSUE WITH COPELAND". The New York Times. 27 August 1919. p. 9. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  139. "INFLUENZA RETURN EXPECTED BY BLUE". The New York Times. 14 September 1919. p. 4. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  140. "PARIS FEARS RETURN OF "FLU" EPIDEMIC". The Sun. 19 August 1919. p. 4. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  141. "British Prepare for Influenza". The New York Times. 30 October 1919. p. 17. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  142. "GRIP IS EPIDEMIC IN JAPAN". The New York Times. 28 December 1919. p. 6. Archived from the original on 17 March 2023. Retrieved 17 March 2023.
  143. 143.0 143.1 "Influenza Gradually Spreading In Japan". The Honolulu Advertiser. 10 January 1920. p. 3. Archived from the original on 17 March 2023. Retrieved 17 March 2023.
  144. 144.0 144.1 "INFLUENZA IN JAPAN". The Sydney Morning Herald. 28 January 1920. p. 10. Archived from the original on 21 March 2023. Retrieved 17 March 2023.
  145. "INFLUENZA". The Age. 26 January 1920. p. 5. Archived from the original on 21 March 2023. Retrieved 17 March 2023.
  146. 146.0 146.1 Richard, S. A.; Sugaya, N.; Simonsen, L.; Miller, M. A.; Viboud, C. (August 2009). "A comparative study of the 1918–1920 influenza pandemic in Japan, USA and UK: mortality impact and implications for pandemic planning". Epidemiology & Infection. 137 (8): 1062–1072. doi:10.1017/S0950268809002088. PMC 2704924. PMID 19215637. Archived from the original on 6 December 2022. Retrieved 20 March 2023.
  147. 147.0 147.1 Vaughan WT (July 1921). "Influenza: An Epidemologic Study". The American Journal of Hygiene. p. 91. Archived from the original on 6 October 2020. Retrieved 13 August 2020.
  148. "300 "FLU" CASES REPORTED". The New York Times. 28 September 1919. p. 5. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  149. "Influenza Spreads in Chicago". The New York Times. 15 January 1920. p. 1. Archived from the original on 22 March 2023. Retrieved 12 April 2022.
  150. "525 NEW CASES IN CHICAGO". The New York Times. 17 January 1920. p. 11. Retrieved 12 April 2022.
  151. "Health Service Reports Influenza Under Control in All Parts of the Country". The Evening Star. 21 January 1920. pp. A2. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  152. "CHICAGO INFLUENZA EPIDEMIC SPREADS". The New York Times. 18 January 1920. p. 14. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  153. "INFLUENZA CASES INCREASE IN CHICAGO". The New York Times. 21 January 1920. p. 32. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  154. "INFLUENZA SHOWS A LARGE INCREASE". The New York Times. 21 January 1920. p. 32. Archived from the original on 22 March 2023. Retrieved 12 April 2022.
  155. "SPREADS IN OTHER CITIES". The New York Times. 23 January 1920. p. 2. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  156. "TOPICS OF THE TIMES". The New York Times. 22 January 1920. p. 16. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  157. 157.0 157.1 "INFLUENZA CASES GROW THROUGHOUT COUNTRY". The New York Times. 25 January 1920. p. 2. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  158. 158.0 158.1 "COPELAND EXPECTS RISE IN INFLUENZA". The New York Times. 27 January 1920. p. 1. Archived from the original on 22 March 2023. Retrieved 12 April 2022.
  159. "Influenza Checked in 25 States". The New York Times. 8 February 1920. p. 15. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  160. "Mortality Statistics 1920" (PDF). 1922. Archived (PDF) from the original on 16 March 2023. Retrieved 20 March 2023 – via CDC. {{cite journal}}: Cite journal requires |journal= (help)
  161. Schmitt, R. C.; Nordyke, E. C. (1999). "Influenza Deaths in Hawai'i, 1918—1920". Hawaiian Journal of History. 33: 101–117. Archived from the original on 5 July 2022. Retrieved 20 March 2023 – via eVols.
  162. Grabowski, M. L.; Kosińska, B.; Knap, J. P.; Brydak, L. B. (12 October 2017). "The Lethal Spanish Influenza Pandemic in Poland". Medical Science Monitor. 23: 4880–4884. doi:10.12659/MSM.906280. PMC 5649514. PMID 29021518.
  163. Erkoreka, A. (9 February 2010). "The Spanish influenza pandemic in occidental Europe (1918–1920) and victim age". Influenza and Other Respiratory Viruses. 4 (2): 81–89. doi:10.1111/j.1750-2659.2009.00125.x. PMC 5779284. PMID 20167048.
  164. Chowell, G.; Viboud, C.; Simonsen, L.; Miller, M. A.; Hurtado, J.; Soto, G.; Vargas, R.; Guzman, M. A.; Ulloa, M.; Munayco, C. V. (22 July 2011). "The 1918–1920 influenza pandemic in Peru". Vaccine. 29 (Suppl 2): B21–B26. doi:10.1016/j.vaccine.2011.02.048. PMC 3144394. PMID 21757099. Archived from the original on 17 March 2023. Retrieved 20 March 2023 – via ScienceDirect.
  165. Kim, T. (2017). "The 1918 Influenza Pandemic and Japanese Government-General of Korea's Preventive Measures against Epidemics". Journal of Humanities, Seoul National University (in Korean). 74 (1): 203–207. Archived from the original on 17 March 2023. Retrieved 20 March 2023 – via Korea Journal Central.{{cite journal}}: CS1 maint: unrecognized language (link)
  166. Hsieh, Y.-H. (October 2009). "Excess Deaths and Immunoprotection during 1918–1920 Influenza Pandemic, Taiwan". Emerging Infectious Diseases. 15 (10): 1617–1619. doi:10.3201/eid1510.080811. PMC 2866376. PMID 19861055. Archived from the original on 16 January 2022. Retrieved 20 March 2023 – via PubMed Central.
  167. Nichols, C. M.; Ewing, E. T.; Gaston, K. H.; Marinari, M.; Lessoff, A.; Huyssen, David (April 2022). "What Came Next?: Reflections on the Aftermath(s) of the 1918–19 Flu Pandemic in the Age of COVID". The Journal of the Gilded Age and Progressive Era. 21 (2): 126. Archived from the original on 27 February 2023. Retrieved 20 March 2023 – via Cambridge Core.
  168. Linnanmäki, E. (2005). Espanjantauti Suomessa — Influenssapandemia 1918-1920 (in suomi). Helsinki: Suomalaisen Kirjallisuuden Seura. p. 69. ISBN 9789517467162.
  169. 169.0 169.1 169.2 Taubenberger, J. K.; Morens, D. M. (2010). "Influenza: The Once and Future Pandemic". Public Health Reports. 125 (Suppl 3): 16–26. PMC 2862331. PMID 20568566. Archived from the original on 2 March 2023. Retrieved 20 March 2023 – via PubMed Central.
  170. Morens, D. M.; Taubenberger, J. K.; Fauci, A. S. (2009). "The Persistent Legacy of the 1918 Influenza Virus". The New England Journal of Medicine. 361: 225–229. doi:10.1056/NEJMp0904819. Archived from the original on 17 March 2023. Retrieved 20 March 2023.
  171. 171.0 171.1 Taubenberger, J. K.; Morens, D. M. (April 2009). "Pandemic influenza – including a risk assessment of H5N1". Scientific and Technical Review. 28 (1): 187–202. PMC 2720801. PMID 19618626. Archived from the original on 9 March 2023. Retrieved 20 March 2023.
  172. 172.0 172.1 172.2 Rozo, M.; Gronvall, G. K. (July–August 2015). "The Reemergent 1977 H1N1 Strain and the Gain-of-Function Debate". mBio. 6 (4). doi:10.1128/mBio.01013-15. PMC 4542197. PMID 26286690. Archived from the original on 18 August 2022. Retrieved 20 March 2023 – via ASM Journals.
  173. Kung, H. C.; Jen, K. F.; Yuan, W. C.; Tien, S. F.; Chu, C. M. (1978). "Influenza in China in 1977: recurrence of influenzavirus A subtype H1N1". Bulletin of the World Health Organization. 56 (6): 913. Archived from the original on 17 March 2023. Retrieved 20 March 2023 – via IRIS.
  174. 174.0 174.1 174.2 174.3 Saunders-Hastings PR, Krewski D (December 2016). "Reviewing the History of Pandemic Influenza: Understanding Patterns of Emergence and Transmission". Pathogens. 5 (4): 66. doi:10.3390/pathogens5040066. PMC 5198166. PMID 27929449.
  175. 175.0 175.1 Crosby 2003.
  176. 176.0 176.1 Worobey M, Cox J, Gill D (2019). "The origins of the great pandemic". Evolution, Medicine, and Public Health. 2019 (1): 18–25. doi:10.1093/emph/eoz001. PMC 6381288. PMID 30805187. S2CID 67863937.
  177. "Grippe : un virus plurimillénaire et ravageur découvert seulement en 1933" [Influenza: a multi-millennial and pest virus discovered only in 1933]. France Culture (in français). 16 January 2019. Retrieved 29 July 2021.
  178. 178.0 178.1 178.2 Valentine V (20 February 2006). "Origins of the 1918 Pandemic: The Case for France". National Public Radio. Archived from the original on 30 April 2009. Retrieved 13 April 2020.
  179. Oxford JS (December 2001). "The so-called Great Spanish Influenza Pandemic of 1918 may have originated in France in 1916". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. Royal Society. 356 (1416): 1857–59. doi:10.1098/rstb.2001.1012. PMC 1088561. PMID 11779384.
  180. 180.0 180.1 Connor S (8 January 2000). "Flu epidemic traced to Great War transit camp". The Guardian. UK. Archived from the original on 8 August 2009. Retrieved 9 May 2009.
  181. 181.0 181.1 Oxford JS, Lambkin R, Sefton A, Daniels R, Elliot A, Brown R, Gill D (January 2005). "A hypothesis: the conjunction of soldiers, gas, pigs, ducks, geese and horses in northern France during the Great War provided the conditions for the emergence of the "Spanish" influenza pandemic of 1918–1919" (PDF). Vaccine. 23 (7): 940–45. doi:10.1016/j.vaccine.2004.06.035. PMID 15603896. Archived from the original (PDF) on 12 March 2020. Retrieved 12 March 2020.
  182. 182.0 182.1 182.2 Shanks GD (January 2016). "No evidence of 1918 influenza pandemic origin in Chinese laborers/soldiers in France". Journal of the Chinese Medical Association. 79 (1): 46–48. doi:10.1016/j.jcma.2015.08.009. PMID 26542935.
  183. 183.0 183.1 Price-Smith 2008.
  184. 184.0 184.1 Hannoun C (1993). "La Grippe". Documents de la Conférence de l'Institut Pasteur. La Grippe Espagnole de 1918. Ed Techniques Encyclopédie Médico-Chirurgicale (EMC), Maladies infectieuses. Vol. 8-069-A-10.
  185. Humphries 2014.
  186. Vergano D (24 January 2014). "1918 Flu Pandemic That Killed 50 Million Originated in China, Historians Say". National Geographic. Archived from the original on 26 January 2014. Retrieved 4 November 2016.
  187. 187.0 187.1 Spinney 2018, p. 143.
  188. 188.0 188.1 Killingray D, Phillips H (2003). The Spanish Influenza Pandemic of 1918–1919: New Perspectives. Routledge. ISBN 978-1-134-56640-2. Archived from the original on 9 May 2021. Retrieved 9 November 2020.
  189. Langford C (2005). "Did the 1918-19 Influenza Pandemic Originate in China?". Population and Development Review. 31 (3): 473–505. doi:10.1111/j.1728-4457.2005.00080.x. JSTOR 3401475.
  190. 190.0 190.1 190.2 190.3 Cheng KF, Leung PC (July 2007). "What happened in China during the 1918 influenza pandemic?". International Journal of Infectious Diseases. 11 (4): 360–64. doi:10.1016/j.ijid.2006.07.009. PMID 17379558.
  191. Vergano D. "1918 Flu Pandemic That Killed 50 Million Originated in China, Historians Say". National Geographic. Archived from the original on 3 March 2020. Retrieved 5 March 2020.
  192. Mills CE, Robins JM, Lipsitch M (December 2004). "Transmissibility of 1918 pandemic influenza". Nature. 432 (7019): 904–06. Bibcode:2004Natur.432..904M. doi:10.1038/nature03063. PMC 7095078. PMID 15602562.
  193. Qureshi 2016, p. 42.
  194. Ewald 1994.
  195. "The Spanish Flu pandemic of 1918". The History Press. Archived from the original on 13 January 2021. Retrieved 20 February 2021.
  196. Illing S (20 March 2020). "The most important lesson of the 1918 influenza pandemic: Tell the damn truth". Vox. Archived from the original on 25 March 2020. John M. Barry : The government lied. They lied about everything. We were at war and they lied because they didn't want to upend the war effort. You had public health leaders telling people this was just the ordinary flu by another name. They simply didn't tell the people the truth about what was happening.
  197. Gladwell 1997, p. 55.
  198. Gladwell 1997, p. 63.
  199. Fogarty International Center. "Summer Flu Outbreak of 1918 May Have Provided Partial Protection Against Lethal Fall Pandemic". Archived from the original on 27 July 2011. Retrieved 19 May 2012.
  200. Gladwell 1997, p. 56.
  201. 201.0 201.1 201.2 201.3 201.4 Spinney 2018, pp. 45–47.
  202. 202.0 202.1 Knobler 2005.
  203. Morris DE, Cleary DW, Clarke SC (2017). "Secondary Bacterial Infections Associated with Influenza Pandemics". Frontiers in Microbiology. 8: 1041. doi:10.3389/fmicb.2017.01041. PMC 5481322. PMID 28690590.
  204. "Bacterial Pneumonia Caused Most Deaths in 1918 Influenza Pandemic". National Institutes of Health. 23 September 2015. Archived from the original on 22 April 2016. Retrieved 17 April 2016.
  205. 205.0 205.1 Taubenberger et al. 2001, pp. 1829–39.
  206. Morens DM, Taubenberger JK, Fauci AS (October 2008). "Predominant role of bacterial pneumonia as a cause of death in pandemic influenza: implications for pandemic influenza preparedness". The Journal of Infectious Diseases. 198 (7): 962–70. doi:10.1086/591708. PMC 2599911. PMID 18710327.
  207. Barry 2004.
  208. 208.0 208.1 Spinney 2018, p. 61.
  209. "Washington State Board of Health pessimistic about influenza pandemic in a report to the governor on January 1, 1919". Archived from the original on 21 July 2020. Retrieved 21 July 2020.
  210. 210.0 210.1 210.2 Spinney 2018, p. 62.
  211. Foxman EF, Storer JA, Fitzgerald ME, Wasik BR, Hou L, Zhao H, et al. (January 2015). "Temperature-dependent innate defense against the common cold virus limits viral replication at warm temperature in mouse airway cells". Proceedings of the National Academy of Sciences of the United States of America. 112 (3): 827–32. Bibcode:2015PNAS..112..827F. doi:10.1073/pnas.1411030112. PMC 4311828. PMID 25561542.
  212. Lowen AC, Steel J (July 2014). "Roles of humidity and temperature in shaping influenza seasonality". Journal of Virology. 88 (14): 7692–95. doi:10.1128/JVI.03544-13. PMC 4097773. PMID 24789791.
  213. Brown JD, Goekjian G, Poulson R, Valeika S, Stallknecht DE (April 2009). "Avian influenza virus in water: infectivity is dependent on pH, salinity and temperature". Veterinary Microbiology. 136 (1–2): 20–26. doi:10.1016/j.vetmic.2008.10.027. PMID 19081209.
  214. Foxman EF, Storer JA, Vanaja K, Levchenko A, Iwasaki A (July 2016). "Two interferon-independent double-stranded RNA-induced host defense strategies suppress the common cold virus at warm temperature". Proceedings of the National Academy of Sciences of the United States of America. 113 (30 Suppl 3): 8496–501. Bibcode:2016PNAS..113.8496F. doi:10.1073/pnas.1601942113. PMC 4968739. PMID 27402752.
  215. Klugman KP, Chien YW, Madhi SA (August 2009). "Pneumococcal pneumonia and influenza: a deadly combination". Vaccine. 27 (s3): C9–C14. doi:10.1016/j.vaccine.2009.06.007. PMID 19683658.
  216. Bengtsson D, Safi K, Avril A, Fiedler W, Wikelski M, Gunnarsson G, et al. (February 2016). "Does influenza A virus infection affect movement behaviour during stopover in its wild reservoir host?". Royal Society Open Science. 3 (2): 150633. Bibcode:2016RSOS....350633B. doi:10.1098/rsos.150633. PMC 4785985. PMID 26998334.
  217. Tolf C, Bengtsson D, Rodrigues D, Latorre-Margalef N, Wille M, Figueiredo ME, et al. (2012). "Birds and viruses at a crossroad – surveillance of influenza A virus in Portuguese waterfowl". PLOS ONE. 7 (11): e49002. Bibcode:2012PLoSO...749002T. doi:10.1371/journal.pone.0049002. PMC 3492218. PMID 23145046.
  218. Tucker MA, Böhning-Gaese K, Fagan WF, Fryxell JM, Van Moorter B, Alberts SC, et al. (January 2018). "Moving in the Anthropocene: Global reductions in terrestrial mammalian movements". Science. 359 (6374): 466–69. Bibcode:2018Sci...359..466T. doi:10.1126/science.aam9712. PMID 29371471.
  219. Blakemore E (3 October 2020). "Catastrophic effect of 1918 flu may have been aided by peculiar influx of cold air into Europe during WWI". The Washington Post. Archived from the original on 11 December 2020. Retrieved 29 November 2020.
  220. Kent L (28 September 2020). "How environmental conditions like cold and wet weather can affect pandemics, and what that means for COVID-19". CNN. Archived from the original on 2 December 2020. Retrieved 29 November 2020.
  221. Powell A (5 October 2020). "Six-year deluge linked to Spanish flu, World War I deaths". Harvard Gazette. Archived from the original on 27 November 2020. Retrieved 29 November 2020.
  222. "Gauze Mask to Halt Spread of Plague". The Washington Times. 27 September 1918. p. 3. Archived from the original on 8 October 2020. Retrieved 5 October 2020.
  223. 223.0 223.1 Hauck G, Gellis K (22 November 2020). "We're celebrating Thanksgiving amid a pandemic. Here's how we did it in 1918 – and what happened next". USA Today. Archived from the original on 21 November 2020.
  224. 224.0 224.1 224.2 224.3 Spinney 2018, pp. 83–84.
  225. 225.0 225.1 225.2 Spinney 2018, pp. 87–88.
  226. Spinney 2018, p. 91.
  227. "How NYC beat deadly 1918 flu without vaccines, lockdowns, mask mandates or school closures". silive. 20 September 2021. Archived from the original on 21 September 2021. Retrieved 23 September 2021.
  228. Bootsma MC, Ferguson NM (May 2007). "The effect of public health measures on the 1918 influenza pandemic in U.S. cities". Proceedings of the National Academy of Sciences of the United States of America. 104 (18): 7588–93. Bibcode:2007PNAS..104.7588B. doi:10.1073/pnas.0611071104. PMC 1849868. PMID 17416677. S2CID 11280273.
  229. Spinney 2018, pp. 109–10.
  230. Spinney 2018, pp. 111–12.
  231. Flecknoe, Daniel; Charles Wakefield, Benjamin; Simmons, Aidan (2018). "Plagues & wars: the 'Spanish Flu' pandemic as a lesson from history". Medicine, Conflict and Survival. 34 (2): 61–68. doi:10.1080/13623699.2018.1472892. PMID 29764189. S2CID 21694687. Archived from the original on 24 July 2022. Retrieved 20 March 2023.
  232. 232.0 232.1 Spinney 2018, p. 92.
  233. Spinney 2018, p. 69.
  234. Spinney 2018, p. 70.
  235. Taubenberger & Morens 2006, p. 19.
  236. Taubenberger & Morens 2006, p. 17.
  237. World Health, Organization (December 2005). "Ten things you need to know about pandemic influenza (update of 14 October 2005)" (PDF). Relevé Épidémiologique Hebdomadaire. 80 (49–50): 428–31. PMID 16372665. Archived (PDF) from the original on 27 July 2021. Retrieved 11 March 2020.
  238. Jilani TN, Jamil RT, Siddiqui AH (14 December 2019). "H1N1 Influenza (Swine Flu)". StatPearls. Treasure Island, FL: StatPearls. PMID 30020613. Archived from the original on 12 March 2020. Retrieved 11 March 2020 – via NCBI.
  239. Johnson & Mueller 2002.
  240. Chandra S, Christensen J (July 2019). "Re: "Reassessing the Global Mortality Burden of the 1918 Influenza Pandemic"". American Journal of Epidemiology. 188 (7): 1404–06. doi:10.1093/aje/kwz044. PMID 30824934. and response Spreeuwenberg P, Kroneman M, Paget J (July 2019). "The Authors Reply" (PDF). American Journal of Epidemiology. 188 (7): 1405–06. doi:10.1093/aje/kwz041. PMID 30824908. Archived from the original (PDF) on 12 March 2020. Retrieved 12 March 2020.
  241. "Historical Estimates of World Population". Archived from the original on 9 July 2012. Retrieved 29 March 2013.
  242. Mayor S (October 2000). "Flu experts warn of need for pandemic plans". BMJ. 321 (7265): 852. doi:10.1136/bmj.321.7265.852. PMC 1118673. PMID 11021855.
  243. Chandra, Kuljanin & Wray 2012.
  244. David Arnold, "Dearth and the Modern Empire: The 1918–19 Influenza Epidemic in India," Transactions of the Royal Historical Society 29 (2019): 181–200.
  245. Sreevatsan A (12 March 2020). "Why 1918 matters in India's corona war". mint. Archived from the original on 18 April 2020. Retrieved 7 June 2020.
  246. "What the history of pandemics tells us about coronavirus". Hindustan Times. 15 April 2020. Archived from the original on 21 April 2020. Retrieved 7 June 2020.
  247. 247.0 247.1 Murray CJ, Lopez AD, Chin B, Feehan D, Hill KH (December 2006). "Estimation of potential global pandemic influenza mortality on the basis of vital registry data from the 1918–20 pandemic: a quantitative analysis". Lancet. Elsevier. 368 (9554): 2211–18. doi:10.1016/S0140-6736(06)69895-4. PMID 17189032. S2CID 22787011. Archived from the original on 27 September 2020. Retrieved 30 September 2020.
  248. "Historiallisia Papereita 1". ISSN 1456-8055. Archived from the original on 6 February 2020. Retrieved 24 June 2020.
  249. Åman M (1990). Spanska sjukan: den svenska epidemin 1918–1920 och dess internationella bakgrund (in svenska). Uppsala; Stockholm: Ubsaliensis Academiae; Distributor, Almqvist & Wiksell International. ISBN 978-91-554-2587-6. OCLC 22451542.
  250. Historical research report from University of Indonesia, School of History, as reported in Emmy Fitri. Looking Through Indonesia's History For Answers to Swine Flu Archived 2 November 2009 at the Wayback Machine. The Jakarta Globe. 28 October 2009 edition.
  251. Kohn 2007.
  252. 252.0 252.1 "İSPANYOL GRİBİNİN DÜNYA VE OSMANLI DEVLETİ ÜZERİNDEKİ ETKİLERİ" (in Türkçe). Archived from the original on 8 November 2020. Retrieved 2 November 2020.
  253. "1918 flu centenary: How to survive a pandemic". Archived from the original on 9 July 2019. Retrieved 19 June 2019.
  254. Rice G, Bryder L. Black November: the 1918 influenza pandemic in New Zealand (Second, revised and enlarged ed.). Christchurch, NZ. ISBN 978-1-927145-91-3. OCLC 960210402.
  255. Radusin M (October 2012). "The Spanish flu – part II: the second and third wave". Vojnosanitetski Pregled. 69 (10): 917–27. PMID 23155616. Archived from the original on 9 July 2020. Retrieved 23 April 2020.
  256. 256.0 256.1 "Epidemics and pandemics in Victoria: Historical perspectives". Parliament of Victoria. 23 April 2020. Archived from the original on 14 September 2022. Retrieved 14 September 2022.
  257. "Influenza pandemic". National Museum of Australia. Archived from the original on 14 September 2022. Retrieved 14 September 2022.
  258. "1918–1920 – Influenza and Pneumonia Pandemic – Nationwide ~820,000–850,000 – Deadliest American Disasters and Large-Loss-of-Life Events". Archived from the original on 30 May 2020. Retrieved 22 May 2020.
  259. The Great Pandemic: The United States in 1918–1919, U.S. Department of Health & Human Services.
  260. "The silent invader – Digital Collections – National Library of Medicine". Archived from the original on 24 July 2020. Retrieved 15 April 2020.
  261. "Flu Epidemic Hit Utah Hard in 1918, 1919". Deseret News. 28 March 1995. Archived from the original on 30 November 2012. Retrieved 7 July 2012.
  262. "The Great Pandemic of 1918: State by State". 5 March 2018. Archived from the original on 6 May 2009. Retrieved 4 May 2009.
  263. "A deadly virus rages throughout Canada at the end of the First World War". CBC History.
  264. "A gripe espanhola no Brasil – Elísio Augusto de Medeiros e Silva, empresário, escritor e membro da AEILIJ" (in português). Jornal de Hoje. Archived from the original on 2 February 2014. Retrieved 22 January 2014.
  265. "The "bird flu" that killed 40 million". BBC News. 19 October 2005. Archived from the original on 7 November 2017. Retrieved 26 April 2009.
  266. Hays 1998.
  267. Marcus H (1996). Haile Sellassie I: The formative years, 1892–1936. Trenton, NJ: Red Sea Press. pp. 36ff.
  268. Pankhurst 1991, pp. 48f.
  269. Pankhurst 1991, p. 63.
  270. 270.0 270.1 270.2 Spinney 2018, pp. 167–69.
  271. "Viruses of mass destruction". Fortune. CNN. 1 November 2004. Archived from the original on 6 May 2009. Retrieved 30 April 2009.
  272. Spinney 2018, p. 134.
  273. "The Flu Pandemic hit Nenana 100 Years Ago". 27 October 2021. Archived from the original on 13 April 2022. Retrieved 12 April 2022.
  274. 274.0 274.1 Denoon 2004.
  275. Wishart S (July–August 2018). "How the 1918 flu spread". New Zealand Geographic (152): 23. Archived from the original on 3 August 2018. Retrieved 3 August 2018.
  276. Afkhami 2003; Afkhami 2012.
  277. FitzGerald J. "Coronavirus: forgotten lessons of the Spanish flu pandemic". The Irish Times. Archived from the original on 5 May 2020. Retrieved 14 June 2020. Yet the "Spanish" flu epidemic of 1918–19 resulted in about 25,000 extra deaths in Ireland, many of them young adults. This was almost as many deaths as occurred among the Irish fighting in the First World War.
  278. "Official Ireland Statistics Office". Central Statistics Office Ireland. Archived from the original on 14 June 2020. Retrieved 14 June 2020. Total deaths in Ireland 1916: 50,627
  279. Phillips H. "South Africa bungled the Spanish flu in 1918. History mustn't repeat itself for COVID-19". The Conversation. Archived from the original on 13 June 2020. Retrieved 26 May 2020.
  280. Spinney 2018, p. 72.
  281. Pankhurst 1991, pp. 51ff.
  282. "Influenza of 1918 (Spanish Flu) and the US Navy". Archived from the original on 11 January 2015. Retrieved 14 May 2009.
  283. Bell D, Nicoll A, Fukuda K, Horby P, Monto A, Hayden F, et al. (January 2006). "Non-pharmaceutical interventions for pandemic influenza, international measures". Emerging Infectious Diseases. 12 (1): 81–7. doi:10.3201/eid1201.051370. PMC 3291414. PMID 16494722.
  284. 284.0 284.1 Shanks GD, Brundage JF (February 2013). "Pacific islands which escaped the 1918-1919 influenza pandemic and their subsequent mortality experiences". Epidemiology and Infection. 141 (2): 353–6. doi:10.1017/S0950268812000866. PMC 9152047. PMID 22564320. S2CID 23794327.
  285. Ryan J, ed. (2009). Pandemic Influenza: Emergency planning and community preparedness. Boca Raton, FL: CRC Press. p. 24.
  286. "Colonial Annual Report", 1919
  287. 287.0 287.1 Iijima W (2003). "Spanish influenza in China, 1918–1920: a preliminary probe". In Phillips H, Killingray D (eds.). The Spanish Flu Pandemic of 1918: New Perspectives. London and New York: Routledge. pp. 101–09.
  288. Killingray D, Phillips H (2003). The Spanish Influenza Pandemic of 1918–1919: New Perspectives. Routledge. ISBN 978-1-134-56640-2. Archived from the original on 27 July 2021. Retrieved 9 November 2020.
  289. Killingray D, Phillips H (2003). The Spanish Influenza Pandemic of 1918–1919: New Perspectives. Routledge. ISBN 978-1-134-56640-2. Archived from the original on 27 July 2021. Retrieved 9 November 2020.
  290. Iijima W (1998). The Spanish influenza in China, 1918–1920. OCLC 46987588.
  291. Iijima W (1998). The Spanish influenza in China, 1918–1920. Spanish 'Flu 1918–1998: Reflections on the Influenza Pandemic of 1918 after 80 Years. Cape Town, South Africa. Archived from the original on 11 April 2020. Retrieved 11 April 2020.
  292. 292.0 292.1 292.2 292.3 292.4 292.5 292.6 292.7 Killingray D, Phillips H (2003). The Spanish Influenza Pandemic of 1918–1919: New Perspectives. Routledge. p. 105. ISBN 978-1-134-56640-2. Archived from the original on 27 July 2021. Retrieved 9 November 2020.
  293. Alita XP, Ling T, Bin ZH, Xiao-ting LI (2010). "Epidemic analysisi of 1918 Spanish influenza in China based on literatures". Journal of Medical Informatics. 31 (1): 47–50. Archived from the original on 29 July 2021. Retrieved 20 March 2023.
  294. Hong NH (2015). "Epidemic Analysis of 1918 Influenza in China – Research on Huolu County in Zhili Province". Historical Research in Auhui.
  295. 295.0 295.1 295.2 Simonsen et al. 1998.
  296. Hanssen, Olav. Undersøkelser over influenzaens optræden specielt i Bergen 1918–1922. Bg. 1923. 66 s. ill. (Haukeland sykehus. Med. avd. Arb. 2) (Klaus Hanssens fond. Skr. 3)
  297. Knobler SL, Mack A. "Institute of Medicine (US) Forum on Microbial Threats". NCBI. Archived from the original on 23 December 2020. Retrieved 17 August 2021.
  298. Barry 2004, p. 239.
  299. "Key Facts about Swine Influenza". Archived from the original on 5 May 2009. Retrieved 30 April 2009.
  300. 300.0 300.1 300.2 300.3 300.4 300.5 Spinney 2018, pp. 180–82.
  301. 301.0 301.1 301.2 301.3 Spinney 2018, pp. 183–84.
  302. Mamelund SE (February 2006). "A socially neutral disease? Individual social class, household wealth and mortality from Spanish influenza in two socially contrasting parishes in Kristiania 1918–19". Social Science & Medicine. 62 (4): 923–40. doi:10.1016/j.socscimed.2005.06.051. PMID 16084634.
  303. He et al. 2011.
  304. He et al. 2013.
  305. "The 'Spanish' Influenza pandemic and its relation to World War I". World War I Centenary. University of Oxford JISC. Archived from the original on 5 August 2020. Retrieved 11 August 2020.
  306. Garret 2007.
  307. Lindley R. "The Forgotten American Pandemic: Historian Dr. Nancy K. Bristow on the Influenza Epidemic of 1918". Archived from the original on 8 August 2014. Retrieved 4 August 2014.
  308. "What can the Spanish Flu teach us about the COVID-19 pandemic?". World Economic Forum. 2 April 2020. Archived from the original on 9 April 2020. Retrieved 8 April 2020.
  309. Correia S, Luck S, Verner E (2020). "Pandemics Depress the Economy, Public Health Interventions Do Not: Evidence from the 1918 Flu". SSRN Working Paper Series. arXiv:2207.11636. doi:10.2139/ssrn.3561560. ISSN 1556-5068. S2CID 216202133. Archived from the original on 27 July 2021. Retrieved 14 April 2020.
  310. Kemp, John (7 April 2020). "RPT-COLUMN-Coronavirus lockdowns: can we learn from the 1918 influenza pandemic? Kemp". Reuters. Archived from the original on 17 August 2021. Retrieved 17 August 2021.
  311. Almond D (1 August 2006). "Is the 1918 Influenza Pandemic Over? Long‐Term Effects of In Utero Influenza Exposure in the Post‐1940 U.S. Population". Journal of Political Economy. 114 (4): 672–712. doi:10.1086/507154. ISSN 0022-3808. S2CID 20055129.
  312. Beach B, Ferrie JP, Saavedra MH (2018). "Fetal shock or selection? The 1918 influenza pandemic and human capital development". doi:10.3386/w24725. Archived from the original on 18 June 2018. Retrieved 18 June 2018.
  313. Vilensky, Foley & Gilman 2007.
  314. Fottrell Q (25 August 2020). "Another warning from the 1918 flu for COVID-19: 'Survival does not mean that individuals fully recovered'". MarketWatch. Archived from the original on 24 August 2020.
  315. Honigsbaum 2008.
  316. Beiner, Guy (2021). "Rediscovering the Great Flu between Pre-Forgetting and Post-Forgetting". In Beiner, Guy (ed.). Pandemic Re-Awakenings: The Forgotten and Unforgotten 'Spanish' Flu of 1918–1919. Oxford University Press. pp. 346–376. ISBN 9780192843739.
  317. Beiner, Guy (2022). "The Great Flu between Remembering and Forgetting". In Beiner, Guy (ed.). Pandemic Re-Awakenings: The Forgotten and Unforgotten 'Spanish' Flu of 1918–1919. Oxford University Press. pp. 1–48. ISBN 9780192843739.
  318. Morrisey 1986.
  319. Benedict & Braithwaite 2000, p. 38.
  320. Crosby 2003, pp. 320–22.
  321. Ball S (13 February 2012). "Downton Abbey, Season Two, Episode Six Recap: Nobody Expects the Spanish Influenza!". Vanity Fair. Archived from the original on 23 October 2020. Retrieved 9 December 2020.
  322. Donoghue, Emma (18 May 2020). "THE PULL OF THE STARS | KIRKUS REVIEWS". Kirkus Reviews. Archived from the original on 21 November 2022. Retrieved 20 March 2023.
  323. Meyer R (29 April 2016). "Human extinction isn't that unlikely". The Atlantic. Archived from the original on 1 May 2016. Retrieved 6 February 2018.
  324. "WHO Coronavirus Disease (COVID-19) Dashboard". WHO. Archived from the original on 16 April 2020. Retrieved 27 February 2021.
  325. Hilleman MR (August 2002). "Realities and enigmas of human viral influenza: pathogenesis, epidemiology and control". Vaccine. 20 (25–26): 3068–87. doi:10.1016/S0264-410X(02)00254-2. PMID 12163258.
  326. Potter CW (October 2001). "A history of influenza". Journal of Applied Microbiology. 91 (4): 572–9. doi:10.1046/j.1365-2672.2001.01492.x. PMID 11576290.
  327. 327.0 327.1 327.2 327.3 Valleron AJ, Cori A, Valtat S, Meurisse S, Carrat F, Boëlle PY (May 2010). "Transmissibility and geographic spread of the 1889 influenza pandemic". Proceedings of the National Academy of Sciences of the United States of America. 107 (19): 8778–81. Bibcode:2010PNAS..107.8778V. doi:10.1073/pnas.1000886107. PMC 2889325. PMID 20421481.
  328. "The Russian Flu of 1889: The Deadly Pandemic Few Americans Took Seriously". HISTORY. 3 October 2023. Retrieved 28 February 2024.
  329. Mills CE, Robins JM, Lipsitch M (December 2004). "Transmissibility of 1918 pandemic influenza". Nature. 432 (7019): 904–6. Bibcode:2004Natur.432..904M. doi:10.1038/nature03063. PMC 7095078. PMID 15602562.
  330. 330.0 330.1 330.2 330.3 330.4 Biggerstaff M, Cauchemez S, Reed C, Gambhir M, Finelli L (September 2014). "Estimates of the reproduction number for seasonal, pandemic, and zoonotic influenza: a systematic review of the literature". BMC Infectious Diseases. 14 (1): 480. doi:10.1186/1471-2334-14-480. PMC 4169819. PMID 25186370.
  331. Taubenberger JK, Morens DM (January 2006). "1918 Influenza: the mother of all pandemics". Emerging Infectious Diseases. 12 (1): 15–22. doi:10.3201/eid1201.050979. PMC 3291398. PMID 16494711.
  332. 332.0 332.1 332.2 332.3 332.4 332.5 332.6 332.7 "Report of the Review Committee on the Functioning of the International Health Regulations (2005) in relation to Pandemic (H1N1) 2009" (PDF). 5 May 2011. p. 37. Archived (PDF) from the original on 14 May 2015. Retrieved 1 March 2015.
  333. Spreeuwenberg P, Kroneman M, Paget J (December 2018). "Reassessing the Global Mortality Burden of the 1918 Influenza Pandemic". American Journal of Epidemiology. 187 (12): 2561–2567. doi:10.1093/aje/kwy191. PMID 30202996.
  334. Morens DM, Fauci AS (April 2007). "The 1918 influenza pandemic: insights for the 21st century". The Journal of Infectious Diseases. 195 (7): 1018–28. doi:10.1086/511989. PMID 17330793.
  335. Johnson NP, Mueller J (2002). "Updating the accounts: global mortality of the 1918-1920 "Spanish" influenza pandemic". Bulletin of the History of Medicine. 76 (1): 105–15. doi:10.1353/bhm.2002.0022. PMID 11875246.
  336. "Why the coronavirus outbreak isn't likely to be a repeat of the 1918 Spanish flu". Los Angeles Times. 6 March 2020. Retrieved 17 February 2024.
  337. Jackson, Claire (1 August 2009). "History lessons: the Asian Flu pandemic". The British Journal of General Practice. 59 (565): 622–623. doi:10.3399/bjgp09X453882. ISSN 0960-1643. Retrieved 25 February 2024.
  338. Jester, Barbara J.; Uyeki, Timothy M.; Jernigan, Daniel B. (2020). "Fifty Years of Influenza A(H3N2) Following the Pandemic of 1968". American Journal of Public Health. 110 (5): 669–676. doi:10.2105/AJPH.2019.305557. ISSN 0090-0036.
  339. Schwarzmann, Stephen W. (1 June 1971). "Bacterial Pneumonia During the Hong Kong Influenza Epidemic of 1968-1969". Archives of Internal Medicine. 127 (6): 1037. doi:10.1001/archinte.1971.00310180053006. ISSN 0003-9926.
  340. Donaldson LJ, Rutter PD, Ellis BM, Greaves FE, Mytton OT, Pebody RG, Yardley IE (December 2009). "Mortality from pandemic A/H1N1 2009 influenza in England: public health surveillance study". BMJ. 339: b5213. doi:10.1136/bmj.b5213. PMC 2791802. PMID 20007665.
  341. "First Global Estimates of 2009 H1N1 Pandemic Mortality Released by CDC-Led Collaboration". Centers for Disease Control and Prevention (CDC). 25 June 2012. Retrieved 7 July 2012.
  342. Kelly H, Peck HA, Laurie KL, Wu P, Nishiura H, Cowling BJ (5 August 2011). "The age-specific cumulative incidence of infection with pandemic influenza H1N1 2009 was similar in various countries prior to vaccination". PLOS One. 6 (8): e21828. Bibcode:2011PLoSO...621828K. doi:10.1371/journal.pone.0021828. PMC 3151238. PMID 21850217.
  343. Dawood FS, Iuliano AD, Reed C, Meltzer MI, Shay DK, Cheng PY, et al. (September 2012). "Estimated global mortality associated with the first 12 months of 2009 pandemic influenza A H1N1 virus circulation: a modelling study". The Lancet. Infectious Diseases. 12 (9): 687–95. doi:10.1016/S1473-3099(12)70121-4. PMID 22738893.
  344. Riley, Steven; Kwok, Kin O.; Wu, Kendra M.; Ning, Danny Y.; Cowling, Benjamin J.; Wu, Joseph T.; Ho, Lai-Ming; Tsang, Thomas; Lo, Su-Vui; Chu, Daniel K. W.; Ma, Edward S. K. (21 June 2011). "Epidemiological Characteristics of 2009 (H1N1) Pandemic Influenza Based on Paired Sera from a Longitudinal Community Cohort Study". PLOS Medicine. 8 (6): e1000442. doi:10.1371/journal.pmed.1000442. ISSN 1549-1676. PMC 3119689. PMID 21713000.
  345. Wong, Jessica Y.; Kelly, Heath; Ip, Dennis K. M.; Wu, Joseph T.; Leung, Gabriel M.; Cowling, Benjamin J. (November 2013). "Case fatality risk of influenza A(H1N1pdm09): a systematic review". Epidemiology (Cambridge, Mass.). 24 (6). doi:10.1097/EDE.0b013e3182a67448. ISSN 1044-3983. PMC 3809029. PMID 24045719.
  346. "WHO Europe – Influenza". World Health Organization (WHO). June 2009. Archived from the original on 17 June 2009. Retrieved 12 June 2009.
  347. "Key Facts About Influenza (Flu)". Centers for Disease Control and Prevention. 2 May 2023. Retrieved 17 February 2024.
  348. Tokars JI, Olsen SJ, Reed C (May 2018). "Seasonal Incidence of Symptomatic Influenza in the United States". Clinical Infectious Diseases. 66 (10): 1511–1518. doi:10.1093/cid/cix1060. PMC 5934309. PMID 29206909.
  349. "Influenza: Fact sheet". World Health Organization (WHO). 6 November 2018. Archived from the original on 17 December 2019. Retrieved 25 January 2020.
  350. "H1N1 fatality rates comparable to seasonal flu". The Malaysian Insider. Washington, D.C., USA. Reuters. 17 September 2009. Archived from the original on 20 October 2009. Retrieved 26 September 2009.
  351. "Open Collections Program: Contagion, Spanish Influenza in North America, 1918–1919". Archived from the original on 20 November 2016. Retrieved 22 November 2016.
  352. Harder TC, Ortrud W. "Chapter Two: Avian Influenza". Influenza Report 2006. published online. Archived from the original on 9 August 2017. Retrieved 26 October 2007. Sometimes a virus contains both avian-adapted genes and human-adapted genes. Both the H2N2 and H3N2 pandemic strains contained avian flu virus RNA segments. "While the pandemic human influenza viruses of 1957 (H2N2) and 1968 (H3N2) arose through reassortment between human and avian viruses, the influenza virus causing the 'Spanish flu' in 1918 appears to be entirely derived from an avian source (Belshe 2005).
  353. 353.0 353.1 Taubenberger et al. 2005.
  354. Antonovics, Hood & Baker 2006.
  355. Vana & Westover 2008.
  356. dos Reis, Hay & Goldstein 2009.
  357. "Researchers reconstruct 1918 pandemic influenza virus; effort designed to advance preparedness". Center for Disease Control. Archived from the original on 19 October 2011. Retrieved 2 September 2009.
  358. "Closing In On a Killer: Scientists Unlock Clues to the Spanish Influenz Virus". National Museum of Health and Medicine. Archived from the original on 2 May 2020. Retrieved 23 March 2020.
  359. Kolata G (16 February 1999). "Scientists Uncover Clues To Flu Epidemic of 1918". The New York Times. Archived from the original on 22 March 2020. Retrieved 23 March 2020.
  360. Kobasa & et al. 2007.
  361. "Research on monkeys finds resurrected 1918 flu killed by turning the body against itself". USA Today. Archived from the original on 5 March 2009. Retrieved 14 August 2008.
  362. "Body exhumed in fight against flu". BBC News. Archived from the original on 17 September 2008. Retrieved 16 September 2008.
  363. In Search of Spanish Flu (documentary). BBC Four.
  364. Fox 2008.
  365. Fox 2010.
  366. Crosby 1976, p. 295.
  367. Madhav 2013.
  368. Branswell H (5 December 2018). "A shot-in-the-dark e-mail leads to a century-old family treasure – and hope of cracking a deadly flu's secret". Stat. Archived from the original on 5 December 2018. Retrieved 5 December 2018.
  369. Hammond JA, Rolland W, Shore TH (14 July 1917). "Purulent bronchitis: A study of cases occurring amongst the British troops at a base in France". The Lancet. 190 (4898): 41–45. doi:10.1016/S0140-6736(01)56229-7. Archived from the original on 27 July 2021. Retrieved 8 December 2018. PDF version here Archived 26 August 2019 at the Wayback Machine
  370. "The Influenza Pandemic of 1918". World War 1 Centenary. Oxford, England: University of Oxford. Archived from the original on 9 December 2018. Retrieved 8 December 2018.
  371. Yu, X.; Tsibane, T.; McGraw, P. A.; House, F. S.; Keefer, C. J.; Hicar, M. D.; Tumpey, T. M.; Pappas, C.; Perrone, L. A.; Martinez, O.; Stevens, J.; Wilson, I. A.; Aguilar, P. V.; Altschuler, E. L.; Basler, C. F.; Crowe Jr, J. E. (2008). "Neutralizing antibodies derived from the B cells of 1918 influenza pandemic survivors". Nature. 455 (7212): 532–536. Bibcode:2008Natur.455..532Y. doi:10.1038/nature07231. PMC 2848880. PMID 18716625. Archived from the original on 16 October 2021. Retrieved 24 October 2021.
  372. Sawchuk LA (August 2009). "Brief communication: Rethinking the impact of the 1918 influenza pandemic on sex differentials in mortality". American Journal of Physical Anthropology. 139 (4): 584–90. doi:10.1002/ajpa.21022. PMID 19280673. Archived from the original on 27 July 2021. Retrieved 10 December 2020.
  373. Noymer A, Garenne M (September 2000). "The 1918 influenza epidemic's effects on sex differentials in mortality in the United States". Population and Development Review. 26 (3): 565–81. doi:10.1111/j.1728-4457.2000.00565.x. PMC 2740912. PMID 19530360.
  374. Paskoff T, Sattenspiel L (January 2019). "Sex- and age-based differences in mortality during the 1918 influenza pandemic on the island of Newfoundland". American Journal of Human Biology. 31 (1): e23198. doi:10.1002/ajhb.23198. PMID 30488509. S2CID 54122685. Archived from the original on 19 October 2020. Retrieved 10 December 2020.
  375. Rewegan A, Bogaert K, Yan M, Gagnon A, Herring DA (10 September 2015). "The first wave of the 1918 influenza pandemic among soldiers of the Canadian expeditionary force". American Journal of Human Biology. 27 (5): 638–45. doi:10.1002/ajhb.22713. PMID 25820782. S2CID 11033776. Archived from the original on 27 July 2021. Retrieved 10 December 2020.


Further reading


External links