Spanish Flu
The 1918 Pandemic: Spread, Mortality, and Response
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The book explores why the virus was so deadly to young adults, examines wartime censorship that shaped public understanding, and reveals how different communities coped with the outbreak. Chapters detail transmission patterns, symptoms, and mortality rates, while also covering research into the virus's genetic makeup and its legacy in modern medicine.
This detailed account of one of history's deadliest pandemics will help anyone understand how a global health crisis unfolds, how societies respond, and what we can learn from past epidemics to prepare for future ones.
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In the months leading up to 1918, reports emerged from British military hospitals in Étaples, France, and Aldershot, England, describing outbreaks of severe influenza-like illness. Patients showed rapid onset of symptoms, including a distinctive blue-violet discoloration of the face—what doctors called heliotrope cyanosis. As the disease progressed, this dusky appearance became a grim hallmark, especially among those who did not survive. The condition earned the grim nickname 'purple death' from those witnessing its terrible toll.
The physicians in Aldershot later reported in The Lancet that the condition they and others had described in 1916 and 1917—what they called "influenza pneumococcal purulent bronchitis"—was essentially the same illness as the one now spreading through the pandemic. That specific term, “purulent bronchitis,” wasn’t yet tied to the same A/H1N1 virus that would come to define this outbreak, but it may have been an early version of the disease.
In 1918, a severe illness emerged in Kansas, United States, during late spring. At the time, people referred to it as 'epidemic influenza,' though others called it 'the grip,' which is 'la grippe' in French or 'grasp' in English. Early reports from Spain began appearing on May 21. Both locations described the disease as 'three-day fever.'
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The disease spread fast, and soon outside of Spain it was misnamed “Spanish influenza.” A report in The Times of London on 2 June 1918, from a correspondent in Madrid, described over 100,000 victims of “The unknown disease...clearly of a gripal character,” without using the term “Spanish influenza” directly. Three weeks later, The Times said, “Everybody thinks of it as the ‘Spanish’ influenza to-day.” Then, just days after that, an advertisement appeared in the same paper for Formamint tablets to prevent “Spanish influenza.” When the illness reached Moscow, Pravda announced, “Ispánka (the Spanish lady) is in town,” giving another common name to the disease.
The outbreak did not begin in Spain, but the name “Spanish flu” became widely used because of how wartime censorship shaped what people knew. Other countries suppressed reports of the disease to maintain morale, while Spain, staying neutral and free from propaganda pressure, published openly about its impact. This made it appear as though the illness originated there. Spanish health officials were unaware their neighboring nations faced similar outbreaks. In fact, in a letter written in October 1918, a Spanish official expressed surprise at learning other countries were affected, noting that people there referred to the illness as the “Spanish grip.” He asked, “And wherefore Spanish?” Adding, “this epidemic was not born in Spain, and this should be recorded as a historic vindication.”
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In the spring of 1918, British and German soldiers gave it different names tied to the battlefield in Belgium where many fell ill—British troops called it 'Flanders flu', while Germans used 'Flandern-Fieber', or Flemish fever. The French press initially referred to it as 'American flu' but later adopted 'Spanish flu' to avoid offending an ally. In Senegal, people called it 'Brazilian flu', and in Brazil, 'German flu'. In Spain itself, the illness was labeled 'French flu'—gripe francesa—or the 'Naples Soldier'—Soldado de Nápoles—after a popular song from a zarzuela. Although 'Spanish flu' (gripe española) became widely used in Spain, it remains a controversial term there.
In Poland, the 1918 flu was called the 'Bolshevik disease', while in Russia people referred to it as the 'Kirghiz disease'. Among some African populations, it was described as a 'white man's sickness'. In South Africa, white residents used the term 'kaffersiekte' — meaning 'negro disease' — as an ethnophaulism. Meanwhile, in Japan, sumo wrestlers were blamed for introducing the illness from Taiwan, leading locals to nickname it 'sumo flu' or 'Sumo Kaze'.
The World Health Organization updated its guidelines in 2015 to help prevent stigma during health crises, advising against linking new diseases with culturally significant names. That includes avoiding terms like “Spanish flu,” which the organization lists as an example of what to steer clear of. Because of this, many authors now choose not to call the 1918 pandemic the Spanish flu. Instead, they refer to it by variations of the phrase “1918–19/20 flu/influenza pandemic.”
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A virologist named John Oxford has suggested that the major UK troop staging and hospital camp in Étaples, France, was likely the center of the Spanish flu. His study showed that in late 1916, the Étaples camp was struck by a new disease with high mortality, causing symptoms similar to the flu. According to Oxford, a similar outbreak happened in March 1917 at army barracks in Aldershot, and military pathologists later identified those early cases as being the same disease as the Spanish flu.
The overcrowded camp and hospital at Étaples was a breeding ground for a respiratory virus. Oxford and his team believed a precursor virus, carried by birds, mutated and moved into pigs kept near the front lines. The site also housed a piggery, and poultry was regularly brought in to feed the animals. At the same time, the hospital dealt with thousands of casualties from poison gas attacks and other war injuries. This combination of conditions made it easy for the virus to jump from animals to humans.
A report in the Journal of the Chinese Medical Association in 2016 pointed to evidence that the 1918 virus was already spreading among European armies well before the pandemic began. Political scientist Andrew Price-Smith shared findings from Austrian archives, suggesting the flu may have started in Austria as early as 1917.
In 1918, the Spanish flu hit Europe hard, with mortality rates reaching their highest point during October and November across all fourteen countries studied. This sudden, widespread peak in deaths happened at the same time in every place, which surprised scientists. Usually, when a virus spreads from one location, it takes longer to reach different areas. But this pattern didn’t match that expectation, suggesting the flu may not have started in Europe at all. Instead, it likely came from somewhere else and spread quickly to every corner of the continent at once.
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Claude Hannoun, who led the study of the Spanish flu at the Pasteur Institute, stated in 1993 that the original virus likely came from China. According to him, it then changed while spreading in the United States, near Boston. From there, it moved to Brest, France, and from Europe’s battlefields, it spread across the world. Hannoun believed Allied forces were the main reason for its global spread. He also considered other possibilities such as Spain, Kansas, and Brest, but found those less probable.
In 2014, historian Mark Humphries of the Memorial University of Newfoundland proposed that the movement of 96,000 Chinese laborers to work behind British and French lines could have introduced the pandemic. He uncovered archival records showing a respiratory outbreak in northern China during November 1917. By the following year, Chinese health officials recognized this illness as the same as the Spanish flu. Though no tissue samples remain for comparison today, reports of sickness were noted along the route these workers took to reach Europe, a path that also went through North America.
China was one of the few regions that seemed less affected by the Spanish flu pandemic, with studies showing a relatively mild flu season in 1918. This has led some to speculate the outbreak may have started there, possibly because the population had earlier immunity. In Guangdong Province, early cases were reported to hit young men especially hard. The June outbreak mainly infected children and adolescents between 11 and 20 years old, while the October wave was most common among those aged 11 to 15.
A 2016 report in the Journal of the Chinese Medical Association looked into whether the 1918 flu came to Europe through Chinese or Southeast Asian soldiers and workers. It found no proof the virus was brought over by them, and instead showed it was already spreading in Europe before the pandemic. The study noted that the low flu death rate among these Asian workers—about one in a thousand—was similar to what was seen in other Allied troops in France by late 1918. That suggests they weren’t carrying a new, more dangerous strain. Also, the workers entered Europe through routes that didn’t lead to detectable outbreaks, making it unlikely they were the original source of the disease.
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The 1918 pandemic is usually dated from March 4th, when a case was recorded involving Albert Gitchell, an army cook at Camp Funston in Kansas. But cases had already appeared earlier—in Haskell County as early as January 1918—prompting local doctor Loring Miner to warn editors of the U.S. Public Health Service's journal Public Health Reports. Within days of that first case at Camp Funston, 522 men at the camp were sick. By March 11th, the virus had reached Queens, New York. Preventive steps taken in March and April were later criticized.
As the U.S. entered World War I, the disease spread fast from Camp Funston, a major army training camp, to other U.S. Army bases and across Europe. By April 1918, it had become an epidemic in the Midwest, East Coast, and French ports, reaching the Western Front by mid-April. From there, it moved quickly through France, Great Britain, Italy, and Spain. In May, cases appeared in Wrocław and Odessa. After the Treaty of Brest-Litovsk was signed in March 1918, Germany released Russian prisoners of war who carried the disease back to their homeland. The infection reached North Africa, India, and Japan in May, and likely spread globally by April, when cases were recorded in Southeast Asia. An outbreak was reported in China in June, and by July the wave had started to fade after reaching Australia.
The first wave of the 1918 pandemic began in early 1918 and lasted through the first part of that year. It was relatively mild compared to what would come later. In the United States, around seventy-five thousand flu-related deaths were reported during the first six months of 1918, which was only slightly higher than the sixty-three thousand deaths recorded in the same period in 1915. In Madrid, Spain, fewer than a thousand people died from influenza between May and June of that year. There were no quarantines put in place. The first wave did disrupt military operations during World War I significantly; three-quarters of French troops, half the British forces, and over nine hundred thousand German soldiers became ill.
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The second wave began in late August 1918, likely spreading from ships in Brest, carried by American troops or French recruits heading to naval training. It reached Boston and Freetown, Sierra Leone, before moving through U.S. military sites like the Boston Navy Yard and Camp Devens, infecting troops bound for Europe. Within two months, it spread across North America and into Central and South America, even reaching Brazil and the Caribbean by ship. July 1918 marked the first cases in the Ottoman Empire among soldiers. From Freetown, the disease moved through West Africa by coast, rivers, and railways, and by September South Africa received it on ships returning members of the South African Native Labour Corps from France. It spread throughout southern Africa and beyond the Zambezi, reaching Ethiopia in November. New York City recorded its first death on 15 September, and just days later, a Liberty Loans Parade in Philadelphia caused an outbreak that would lead to 12,000 deaths.
The second wave of the 1918 pandemic reached Russia in a southwest–northeast diagonal path, and also arrived in Arkhangelsk due to the North Russia intervention. From there, it spread across Asia, following the Russian Civil War and the Trans-Siberian railway, eventually reaching Iran, where it moved through Mashhad. It reached India in September and China and Japan in October. Celebrations marking the Armistice of 11 November 1918 sparked new outbreaks in Lima and Nairobi, though by December, the wave had mostly subsided.
The first wave of the 1918 pandemic had behaved like typical flu outbreaks, with the sick and elderly bearing the brunt, while younger people generally recovered. But the second wave proved far more lethal. October 1918 saw the peak of the entire pandemic’s death toll. In the United States, nearly 292,000 lives were lost between September and December of that year—compared to just around 26,000 during the same months in 1915. The Netherlands logged over 40,000 deaths from influenza and acute respiratory disease. In Bombay, about 15,000 people died out of a population of 1.1 million. And in India, historian David Arnold estimates at least 12 million lives were lost—a full 5% of the population—during the 1918 flu pandemic.
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The pandemic continued into 1919, with activity persisting in many places, possibly influenced by winter weather in the Northern Hemisphere, where influenza typically flares. Still, the outbreak lasted well into that year regardless of region or climate. In the U.S., cases began rising again as early as late November 1918, and the Public Health Service reported a "recrudescence of the disease" in widely scattered localities by early December. This resurgence varied across the country, perhaps due to different restrictions in place. Michigan, for example, saw a quick return of cases that peaked in December, possibly because public gathering bans had been lifted. In response, many areas reimposed measures like school closures and limits on public gatherings in an effort to slow the spread.
In January 1919, most cities across the United States faced a sharp rise in death rates, with nearly all seeing a return of the flu during that month and February. Significant outbreaks struck places like New York City, Los Angeles, Memphis, Nashville, San Francisco, and St. Louis. By mid-February, influenza activity had started to decline nationwide. Still, nearly 160,000 deaths were recorded in the first half of 1919 from pneumonia and influenza. A second wave began to emerge more clearly in Europe later that winter and into spring. England and Wales saw a major outbreak by mid-February, peaking early in March, while France and the Netherlands also experienced significant waves. Norway, Finland, and Switzerland had recrudescences in March, and Sweden’s outbreak occurred in April.
Much of Spain saw a major resurgence of influenza between January and April 1919. Portugal had a second wave from March through September, with worst effects on west coast and north, and all districts hit between April and May. In Australia, flu arrived January 1919, entering through Melbourne where it peaked mid-February, quickly spreading to New South Wales and South Australia. New South Wales had first outbreak mid-March to late May, followed by more severe second wave in Victoria April to June. Queensland wasn't infected until late April, Western Australia until early June, and Tasmania until mid-August. Of six states, Victoria and New South Wales saw most widespread outbreaks, each experiencing another significant wave over winter. Second epidemic in New South Wales was worse than first, while Victoria's third wave was less extensive than second but similar to first.
The third wave of 1919 brought the disease to new places, like Madagascar, where cases appeared in April and spread across the island by June. Hong Kong saw another outbreak in June, and South Africa experienced one during its fall and winter months. New Zealand had some cases in May. In South America, the pandemic resurged throughout 1919—Brazil was hit between January and June, while Chile, first affected in October 1918, saw a severe second wave with peak mortality in August. Montevideo also faced a second outbreak between July and September.
The third wave struck especially hard in places like Spain, Serbia, Mexico, and Great Britain. It brought hundreds of thousands of deaths to these areas. This final surge of the 1918 pandemic left a trail of loss across the regions it touched. The impact was severe enough to be remembered as one of the deadliest parts of the outbreak. These countries faced the worst of this last wave, with death tolls reaching into the hundreds of thousands. The third wave of 1919 marked a devastating chapter in the global spread of the disease.
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As fall approached in the Northern Hemisphere, people began to worry about a return of the flu. Experts pointed to past outbreaks, like the one from 1889 to 1890, to suggest that another wave might happen soon. Not everyone agreed with this prediction, though. In September 1919, U.S. Surgeon General Rupert Blue said that while a return of the flu later in the year was “probably, but by no means certainly” expected, others remained unsure. Meanwhile, France had already started planning a public information campaign before summer ended, and Britain began getting ready in the autumn by making vaccine.
In December, the flu returned to Japan and moved quickly across the country, with people at the time pointing to the cold weather as a key factor. Health officials brought back pandemic measures to try to stop the spread, advising everyone to wear masks. The outbreak grew stronger toward the end of December and reached its peak in January.
Between October 1919 and January 23, 1920, the fourth wave of the 1918 pandemic brought 780,000 cases across the country, with at least 20,000 deaths by that time. This outbreak was said to be three times more severe than the same period in 1918–1919. Still, it was seen as milder than the previous year’s illness, even though it spread more easily. The wave peaked quickly at the start of the year but continued through the winter before easing in the spring.
Throughout the spring and summer of 1919, the United States saw nearly continuous isolated or solitary cases of the flu. By September, scattered cases began to rise noticeably. Chicago had one of the first major outbreaks starting in mid-January. The Public Health Service said it would try to "localize the epidemic," but the disease was already spreading rapidly, causing a simultaneous outbreak in Kansas City. A few days later, the PHS issued another statement saying the disease was under control and that a large-scale outbreak was not expected.
Within days of Chicago’s rapid rise in flu cases, it was clear the disease was moving faster than it had during the winter of 1919, even though deaths were lower. In just a week, new cases there exceeded the peak of the previous wave. Around the same time, New York City also saw a sudden spike, and other cities across the country soon followed. In response, some pandemic measures were reinstated—like closing schools and theaters, and staggering business hours to reduce crowding—in places such as Chicago, Memphis, and New York City. As had happened in the fall of 1918, schools stayed open in New York but were closed in Memphis as part of efforts to limit public gatherings.
The fourth wave in the United States faded just as quickly as it had struck, peaking in early February. The U.S. Mortality Statistics described it later as an epidemic of considerable proportions during the early months of 1920. It caused about one-third the number of deaths compared to the 1918–1919 pandemic. New York City reported 6,374 flu-related deaths between December 1919 and April 1920, nearly twice as many as the first wave in spring 1918. Cities like Detroit, Milwaukee, Kansas City, Minneapolis, and St. Louis were especially hard-hit, with death rates surpassing those of 1918. Hawaii also saw its peak in early 1920, recording 1,489 deaths from flu-related causes—more than in either 1918 or 1919.
Poland saw a terrible outbreak during the winter of 1920, with Warsaw recording a peak of 158 deaths in one week—higher than the 92 deaths in December 1918. Still, this final wave passed quickly, lasting only weeks, unlike the long spread of the 1918–1919 epidemic. In contrast, western Europe faced what was considered a milder outbreak, with death patterns shifting toward those of regular seasonal flu. Countries like Spain, Denmark, Finland, Germany, and Switzerland all saw their final peaks between January and April of 1920.
Mexico saw a fourth wave of the Spanish flu between February and March of 1920. In South America, Peru dealt with what experts called "asynchronous recrudescent waves" throughout the year. A severe third wave hit Lima, the capital, between January and March, leading to an all-cause excess mortality rate about four times higher than during the 1918–1919 wave. Ica also faced another serious pandemic wave in 1920, from July through October. Brazil experienced a fourth wave in February.
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By mid-1920, the pandemic was largely seen as finished, both by the public and by governments. In Chile, however, a third, less severe wave occurred from November 1920 through March 1921. After that, the flu appeared to vanish during the winter of 1920–1921. In the United States, deaths from pneumonia and influenza were "very much lower than for many years."
After the 1918 pandemic, seasonal flu returned in 1921, with a fourth wave hitting seven of Chile’s twenty-four provinces between June and December. The winter of 1921–1922 marked the first major resurgence of flu in the Northern Hemisphere, especially in northwestern Europe. In the Netherlands, all-cause mortality doubled in January 1922 alone. Helsinki experienced its fifth flu epidemic between November and December 1921, and in the United States, California saw flu prevalence in early March 1922 that was greater than any time since the pandemic ended in 1920.
After 1920, the 1918 virus came to be known as the “seasonal flu.” The H1N1 strain stayed around, sometimes leading to more serious or memorable outbreaks. This time since 1918 has been called a “pandemic era,” during which all later flu pandemics were caused by descendants of that original virus. Following the first post-1918 pandemic in 1957, the H1N1 was fully replaced by H2N2, a new strain formed when human H1N1 mixed with an avian influenza virus, and H2N2 became the main flu virus in humans.
In 1977, a virus nearly identical to the seasonal H1N1 strain last seen in the 1950s emerged in the USSR, triggering a small outbreak primarily among those 26 and under. Though some suggest the virus might have remained frozen for two decades, others point to possible human involvement, such as an accidental release from a research lab where it had been preserved. Following this event, the H1N1 virus reappeared and resumed circulation without displacing H3N2, the other active influenza A virus that had replaced H2N2 after the 1968 pandemic. This marked the first instance of two influenza A viruses circulating simultaneously. That pattern persisted even after 2009, when a new H1N1 strain caused another pandemic and then took over the role of the seasonal H1N1, leaving both H1N1 and H3N2 to coexist.
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The Spanish Flu spread rapidly because each infected person typically passed it to between two and three others. The war effort made things worse, with troops moving in close quarters and spreading the virus faster, while also possibly causing more mutations. Being undernourished and stressed from battle may have weakened soldiers' immune systems, making them more likely to get sick. Travel and transportation helped carry the disease around the world. Governments downplayed the threat, which left people unprepared when outbreaks hit.
The second wave of the 1918 flu grew more deadly because of the First World War. In normal civilian life, natural selection favors milder strains—those who get very sick stay home, while those with mild symptoms carry the virus onward. But in the trenches, the pattern reversed. Soldiers with mild cases remained where they were, while the severely ill were transported by train to crowded field hospitals, spreading a more lethal version of the virus. This helped spark the second wave that quickly spread around the world. Health officials today look for deadlier strains when a virus reaches places experiencing social upheaval. Most people who survived the first wave gained immunity, proving it was the same strain. Copenhagen escaped high death rates because its population had already been exposed to the less-fatal first wave, recording only 0.29% total mortality.
After the deadly second wave, new cases fell quickly. In Philadelphia, 4,597 people died in the week ending October 16, but by November 11, the virus had nearly vanished from the city. Some thought doctors became better at treating pneumonia, but John Barry said researchers found no proof for that idea. Another theory is that the 1918 virus changed fast into a less dangerous version. That kind of change happens often with flu viruses, as more deadly strains tend to kill off their hosts. Still, serious cases lasted into 1919. One was Joe Hall, an ice hockey player who died in April after an outbreak that led to canceling the 1919 Stanley Cup Final.
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Most people infected during the first wave of the 1918 pandemic experienced typical flu symptoms like sore throat, headache, and fever. But by the second wave, the illness had become far more deadly, often leading to bacterial pneumonia, which was frequently the cause of death. A more severe form of the disease caused heliotrope cyanosis—starting with mahogany spots over the cheekbones, then turning the face blue, and eventually blackening the extremities and body. Death usually came within hours or days as the lungs filled with fluid. Other symptoms included spontaneous nosebleeds, miscarriages, a strange smell, hair and tooth loss, delirium, dizziness, insomnia, and loss of hearing or smell. 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."
The majority of deaths during the 1918 pandemic were caused by bacterial pneumonia, a common secondary infection that followed influenza. This pneumonia occurred when bacteria from the upper respiratory tract entered the lungs through damaged bronchial tubes. The virus itself also caused death directly by inducing severe lung hemorrhages and swelling. Modern studies have shown the virus triggered an extreme immune response in the body, known as a cytokine storm. It appears that the strong immune reactions in young adults may have contributed more to their deaths, while the weaker responses in children and middle-aged people led to fewer fatalities.
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The Spanish flu pandemic grew more deadly due to unusually cold and wet weather, especially during the second wave in 1918. Climate data and death records from 1914 to 1919 show a major environmental shift across Europe, with heavy rain and dropping temperatures closely matching rising mortality. These conditions likely helped the virus spread more easily while weakening immune systems. Lower temperatures and increased precipitation may have also boosted infections from pneumococcal bacteria, which affected about one-fifth of victims and caused a 36% death rate. The climate anomaly might have influenced the movement of bird species carrying the H1N1 virus, contaminating water sources with infection rates reaching 60% in autumn. Dust from warfare could have added to cloud formation and rainfall, worsening the outbreak.
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In 1918, despite systems in place to warn public health officials of infectious disease outbreaks, influenza was not among reported illnesses, causing delayed response. Still, steps were taken: quarantines were enforced at sea around Iceland, Australia, and American Samoa, helping prevent spread and save lives. Social distancing measures introduced—closing schools, theatres, and churches, limiting public transit, and banning big gatherings. Face masks became widespread in some areas like Japan, though effectiveness was debated. In San Francisco, the Anti-Mask League showed resistance to their use. Vaccines were developed but used bacterial methods rather than targeting virus itself, only assisting with secondary infections. Enforcement differed by location; in New York City, health commissioner instructed businesses to operate on staggered shifts to avoid subway crowding.
A later study showed that actions like stopping large gatherings and making people wear face masks could lower the death rate by as much as half. But this only worked if these measures were put in place early during the outbreak and if they weren’t lifted too soon.
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The Spanish flu spread to roughly 500 million people—about one-third of the global population—and is regarded as one of history's most lethal pandemics. Early figures from 1927 estimated 21.6 million deaths, while a 1991 review suggested a range between 25 and 39 million. By 2005, the death count was believed to be 50 million, possibly as high as 100 million. A 2018 reassessment in the American Journal of Epidemiology put the total at around 17 million, though that estimate has been disputed. In 2021, John M. Barry's research placed the global toll well above 100 million. With a world population of 1.8 to 1.9 billion, these numbers reflect between 1 and 6 percent of people affected. A 2009 study in Influenza and Other Respiratory Viruses, analyzing data from fourteen European countries, found 2.64 million excess deaths during the 1918–1919 pandemic, representing a mortality rate of about 1.1% of Europe's population. The U.K.'s excess mortality rate was estimated at 0.28%–0.4%, much lower than the European average.
India was hit hardest by the 1918 pandemic, with somewhere between 12 and 17 million people dying—about 5% of its population. In areas under British rule, the death toll reached 13.88 million, though some estimates suggest at least 12 million lost their lives. That decade marked the only time in census history when India’s population actually dropped, largely due to the flu. Still, while India is often called the most severely affected country, one study suggests other factors may have contributed to its unusually high death rates, pointing to unusually high mortality in 1917 and wide regional differences. A 2006 study in The Lancet found that Indian provinces saw excess deaths ranging from 2.1% to 7.8%, with people at the time attributing the variation to nutrition and temperature changes. Japan also suffered greatly, losing nearly 500,000 people over two waves between 1918 and 1920.
In the Dutch East Indies, which is now Indonesia, about 1.5 million people died out of a population of 30 million. In Tahiti, 13 percent of the population perished within just one month. Western Samoa saw 22 percent of its 38,000 people die in two months. New Zealand experienced a deadly toll too, with an estimated 6,400 Pākehā—people of European descent— dying in six weeks, along with 2,500 Māori. The Māori were eight times more likely to die than the Pākehā during this time.
In Australia, the flu killed between 12,000 and 20,000 people, with a death rate of 2.7 per 1,000, one of the lowest recorded, yet as much as 40 percent of the population became infected. Some Aboriginal communities saw a mortality rate as high as 50 percent. New South Wales and Victoria had the highest relative death rates, at 3.19 and 2.40 per 1,000 respectively, while Western Australia, Queensland, Southern Australia, and Tasmania saw lower rates of 1.70, 1.14, 1.13, and 1.09 per 1,000. In Queensland, at least one-third of recorded deaths were among Aboriginal people. In the U.S., about 20 million out of 105 million became infected during the 1918–1919 season, with an estimated 500,000 to 850,000 dying—around 0.5 to 0.8 percent of the population. Native American tribes were especially hard-hit; in the Four Corners area, 3,293 Native Americans died. Entire Inuit and Alaskan Native villages vanished in Alaska. Canada lost 50,000 people to the flu.
In Ghana, the 1918 flu epidemic killed at least 100,000 people. In Ethiopia, Tafari Makonnen, who would later become Emperor Haile Selassie, was one of the first in his country to contract the illness but survive. The capital city, Addis Ababa, saw an estimated 5,000 to 10,000 deaths, possibly more. Russia’s death toll is believed by some to be around 450,000, though experts called that figure a “shot in the dark.” If accurate, that would mean roughly 0.4% of Russia’s population died from the flu—lower than most of Europe. Another study suggests the real number may have been closer to 2%, or about 2.7 million people, given the chaos of civil war and broken infrastructure at the time.
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Even in places where death rates were low, countless adults fell sick, leaving daily life grinding to a halt. Some towns shut down all stores or let people place orders outside. Healthcare workers couldn’t care for the sick, and gravediggers couldn’t bury the dead because they were ill too. In many areas, mass graves had to be dug by steam shovel, and bodies were buried without coffins.
In 1918, Bristol Bay, a region of Alaska home to Indigenous people, was hit hard by the flu, with a death rate of 40 percent—some villages vanished entirely. Nenana, Alaska, escaped the worst of the pandemic between 1918 and 1919, but the disease finally reached the town in spring 1920. Reports say that during the first two weeks of May, most of the town’s population became infected, with about 10 percent of residents dying, mostly Alaska Natives.
The 1918 pandemic struck several Pacific island territories especially hard. New Zealand, which was too slow to stop ships from leaving its ports, became a source of infection. The flu reached Tonga, where it killed 8% of the population; Nauru, with 16% mortality; and Fiji, affecting 5% of its people, or about 9,000. Western Samoa was hit worst, having been occupied by New Zealand since 1914. Nearly 90% of its population became infected, with 30% of adult men, 22% of women, and 10% of children dying. The disease spread quickly among the higher social classes, as Indigenous customs required gathering elders on their deathbeds to pass down oral tradition, which led many community leaders to become infected.
In Iran, the pandemic claimed between 902,400 and 2,431,000 lives, which amounted to eight percent to twenty-two percent of the total population. At the same time, the country was enduring the Persian famine of 1917–1919.
In South Africa, around 300,000 people—about 6% of the population—died within six weeks during the 1918 flu pandemic. Government responses at the beginning of the outbreak in September may have unintentionally helped the virus spread faster. In Kimberley, nearly a quarter of the working population, largely diamond mine workers, lost their lives. In British Somaliland, a government official said that 7% of the native people died. The high number of deaths came from an infection rate reaching as high as 50% and the severe symptoms of the illness.
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In the Pacific, American Samoa and New Caledonia kept deaths from influenza to zero by enforcing quarantines. American Samoa delayed the outbreak until 1926, while New Caledonia’s outbreak didn’t arrive until 1921, once quarantine measures ended. On American Samoa, at least 25% of residents became ill, with a 0.1% death rate. In New Caledonia, widespread illness occurred and the same 0.1% of the population died. Australia also avoided the first two waves through quarantine. Iceland protected one-third of its people by closing the main road. By the pandemic’s end, the isolated island of Marajó in Brazil's Amazon Delta had no reported cases, and Saint Helena recorded no deaths.
China’s experience with the 1918 flu remains uncertain because health data wasn’t collected in a centralized way during the Warlord period. Some evidence suggests the country may have had a relatively mild flu season that year, though reports from parts of its interior hint that influenza mortality could have been higher in certain areas. At the very least, there's little sign that China as a whole was seriously impacted by the pandemic compared to other regions around the world.
The first estimate of the Chinese death toll came in 1991 from Patterson and Pyle, who put it between 5 and 9 million. But their study was later criticized for flawed methods, and newer research suggested a much lower number. Iijima, in 1998, estimated between 1 and 1.28 million deaths based on data from Chinese port cities. These lower figures relied on the idea that poor communication kept the flu out of China’s interior. Still, some reports from contemporary newspapers, post offices, and missionary doctors suggest the flu did reach rural areas and was severe in parts of the countryside.
In 1918, while medical records from China’s interior are limited, data from port cities like Hong Kong, Canton, Peking, Harbin, and Shanghai show surprisingly low death rates from the flu. These cities were monitored by the Chinese Maritime Customs Service, largely staffed by foreign workers. Hong Kong reported a mortality rate of 0.25%, and Canton’s was 0.32%. In contrast, places like Calcutta and Bombay saw much higher deaths. Shanghai, with over two million people, recorded only 266 flu-related deaths among its Chinese residents. When extrapolated across China, the overall death rate likely stayed under 1%, far below the global average of three to five percent. Japan and Taiwan had higher rates, around 0.45% and 0.69% respectively.
In Hong Kong and Canton, the true number of flu deaths was likely much higher than what was recorded, because only those who died in colony hospitals were included in the statistics. A similar situation occurred in Shanghai, where data only reflected the area managed by the health section of the International Settlement—meaning the real toll was far greater. Medical records from China’s rural regions show that people living outside of cities were at much higher risk. In Houlu County, Hebei Province, a survey found that in October and November 1918, the case fatality rate reached 9.77 percent, with 0.79 percent of the county's population dying from influenza during those months.
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The 1918 pandemic killed mostly young adults. In 1918–1919, 99% of influenza deaths in the U.S. were people under 65, with nearly half occurring in those aged 20 to 40. Even by 1920, when the death rate among younger people had dropped sixfold, 92% of all deaths still occurred in this age group. That’s unusual because flu typically hits infants and the elderly hardest. Older adults may have been protected by prior exposure to the 1889–1890 pandemic. Historian John M. Barry said pregnant women were especially at risk; in thirteen studies, death rates among hospitalized women ranged from 23% to 71%. Of those who survived childbirth, over one-quarter lost their babies. Another odd feature was that the outbreak spread widely in summer and fall, unlike typical flu seasons that peak in winter.
The Spanish Flu hit different places in wildly different ways. Some parts of Asia saw death rates 30 times higher than others in Europe, and overall, Africa and Asia bore the brunt while Europe and North America fared better. Within continents, the variation was huge—Hungary and Spain had three times more deaths than Denmark, and Sub-Saharan Africa faced two to three times the risk compared to North Africa. In some parts of Asia, the death rate may have been up to ten times higher than in others. Cities were hit harder than rural areas, and even within cities, there were differences that might reflect immunity from an earlier wave or the effects of social distancing measures.
In Oslo, a clear pattern emerged showing how social class affected survival during the 1918 pandemic. People living in smaller apartments died at higher rates, suggesting that crowded and poor living conditions played a major role in mortality. Immigrant communities also faced higher death rates, with Italian Americans nearly twice as likely to die compared to the average American. These differences were tied to worse diets, lack of space, and limited access to healthcare. Yet there was one unexpected twist: African Americans were relatively spared from the worst effects of the outbreak.
More men than women died from the flu, likely because they went out more and were exposed more often, while women tended to stay home. Men were also more likely to already have tuberculosis, which made it much harder to survive. But in India, the pattern was different. There, more women died, possibly because they were given worse food and were expected to care for the sick instead of being cared for themselves.
A study by He et al. from 2011 looked at what caused the different patterns of the 1918 flu outbreak and how those related to deaths and illness. They found that changes over time in how quickly the virus spread best explained the pattern. Another study from 2013 used a simple model to figure out why there were three waves of the pandemic. It looked at school schedules, temperature shifts, and how people changed their behavior during the outbreak. The results showed all three factors mattered, but it was human behavior that had the strongest impact.
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Researchers studying the 1918 pandemic virus found that it closely resembled avian strains, and based on earlier human cases, concluded the virus moved directly from birds to humans, with swine catching it later from people. More recent findings suggest the strain may have begun in a nonhuman mammal between 1882 and 1913. That original virus split around 1913 to 1915 into two lines — one infecting humans, the other pigs. The most recent common ancestor of human strains lived sometime between February 1917 and April 1918. Because pigs are more easily infected by avian flu than humans are, they were likely the original host, passing the virus to people between 1913 and 1918.
In 2005, scientists announced they had successfully rebuilt the 1918 flu virus, an influenza A subtype H1N1, using genetic material from old tissue samples. The work was carried out by researchers from the Centers for Disease Control and Prevention, Mount Sinai School of Medicine, and another lab. They obtained samples from an Inuit woman who died during the pandemic and was buried in Alaskan permafrost, as well as from American soldiers whose remains were preserved. Dr. Terrence Tumpey led the team that used these samples to create RNA segments and reassemble the virus. These recreated virus particles were then tested on mice, ferrets, and macaques to better understand how to prepare for future outbreaks.
In 2007, Kobasa and colleagues found that when monkeys were infected with a recreated version of the 1918 flu virus, they showed the typical symptoms of that pandemic and eventually died because their immune systems overreacted. This could help explain why the Spanish flu was so deadly for younger, healthier people—those with stronger immune systems might have had more severe reactions.
In December 2008, Yoshihiro Kawaoka at the University of Wisconsin led research that connected three specific genes—PA, PB1, and PB2—and a nucleoprotein from Spanish flu samples to the virus’s ability to attack the lungs and cause pneumonia. These genes were then inserted into a modern H1N1 strain, and when tested on animals, they produced similar symptoms.
In 2008, researchers looked at the virus from the 1918 pandemic by studying a specific part called the Hemagglutinin antigen. They tested people who had survived the outbreak and found that all of them showed seroreactivity, meaning their immune systems had responded to the virus. Of those tested, seven out of eight had memory B cells that could produce antibodies targeting the HA antigen. This discovery showed how the immune system can remember and fight off the same virus again.
A group from the Mount Sinai School of Medicine shared findings in June 2010, revealing that immunity from the 2009 flu vaccine offered some defense against the strain responsible for the Spanish flu outbreak.
In 2013, the AIR Worldwide Research and Modeling Group used the AIR Pandemic Flu Model to estimate what a modern outbreak might look like. The model projected that a pandemic similar to the 1918 "Spanish flu" could lead to between $15.3 billion and $27.8 billion in extra life insurance losses just within the United States. It also forecast that such an event could cause between 188,000 and 337,000 deaths across the country.
In 2018, Michael Worobey, a professor at the University of Arizona who studies the 1918 pandemic, shared that he had acquired tissue slides made by William Rolland, a physician who documented a respiratory illness likely caused by the virus while working as a pathologist in the British military during World War One. Worobey used those slides to try to learn more about where the pathogen came from.
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As the decades passed, the Spanish flu grew dim in public memory, especially with the rise of bird flu and other outbreaks in the 1990s and 2000s. Some historians have called it a “forgotten pandemic,” but Guy Beiner has argued otherwise. He showed that while the pandemic was largely ignored in mainstream history and overshadowed by the commemoration of the First World War, it was still kept alive in private and local memories around the world.
The Spanish flu pandemic moved so quickly that most of its victims in the United States died within nine months, which meant limited news coverage. People were already used to seeing outbreaks of diseases like typhoid, yellow fever, diphtheria, and cholera during the late 19th and early 20th centuries, so the flu didn’t stand out as uniquely significant. In some places, the flu wasn’t even reported in the news—sometimes the only mention was in ads for medicines claiming to cure it.
The outbreak came during the First World War, when news of the conflict dominated headlines and public attention. Most people who died from the flu were young adults, just like those killed in battle. In Europe, where the war had already caused massive loss of life, the flu deaths might have felt less shocking or even been seen as part of the ongoing tragedy. The high number of young adult fatalities from both the war and the epidemic made it hard to fully grasp how many died from the flu alone. The psychological impact of the pandemic may not have stuck as strongly because it was so closely tied to the war’s horrors.
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