1918 Spanish Flu Origins / Camp Funston Theory

Introduction

The 1918–1920 influenza pandemic remains the deadliest infectious disease event in recorded history. Estimates of worldwide mortality range from 50 million to 100 million, with some later revisions suggesting the figure may be higher. The pandemic infected an estimated 500 million people — roughly one-third of the world's population at the time — across all inhabited continents. It killed more people in a single year than four years of the First World War.

The name "Spanish flu" is a misnomer with a political origin. Spain was neutral during the First World War and did not impose the same wartime press censorship that suppressed reporting on the pandemic in Britain, France, Germany, and the United States. When King Alfonso XIII fell ill in May 1918, the Madrid press reported openly, and it was the Spanish press that initially circulated news of the epidemic widely. The world came to associate the outbreak with Spain simply because Spain was the country reporting it.

The Three Origin Hypotheses

Hypothesis 1: Camp Funston, Kansas (USA)

The most widely cited theory places the first significant outbreak at Camp Funston, a US Army training facility in Kansas. On 4 March 1918, an army cook reported to the base infirmary; his case is conventionally taken to mark the start of the pandemic in the US, although there were cases before his. Within three weeks, more than 1,100 other soldiers at the camp were sick enough to require hospitalisation, according to Barry. Camp Funston was a major transit point for troops being mobilised and shipped to Europe; if the virus originated or amplified there, its global dispersal via troop movements is a plausible mechanism.

John M. Barry's 2004 book The Great Influenza: The Story of the Deadliest Pandemic in History is the most prominent popular account of the Kansas hypothesis, but Barry's own position is more specific than Camp Funston. In a 2004 article in the Journal of Translational Medicine, he argued that the most likely site of origin was Haskell County, Kansas, in January 1918, with the virus reaching Camp Funston through soldiers from the county and their visitors, while stating that it is impossible to answer the question of origin with absolute certainty. His case is epidemiological and circumstantial: a rural county that raised poultry, cattle and hogs, a physician's report of an unusually severe influenza outbreak, and the timing of the Funston outbreak.

Hypothesis 2: Étaples, France (1916–17)

A competing hypothesis, advanced by the virologist John Oxford and colleagues in a 2002 Lancet Infectious Diseases paper, places the pandemic's origin on the Western Front, pointing to 1916–17 outbreaks at the British Army camp at Étaples in northern France and at Aldershot in England. Those authors argued that these outbreaks caused very high mortality in 25–35 year olds and showed the heliotrope cyanosis that was prominent in 1918, and concluded that on the balance of probability the pandemic began in a European country in the winter of 1916 or 1917. The 1916–17 outbreak at Étaples was first described in The Lancet in 1917 as "purulent bronchitis".

The Étaples hypothesis has the advantage of an earlier timeline and a European locus consistent with early pandemic spread, but relies on retrospective interpretation of pathological records that were not specifically characterised as influenza at the time. The 2019 Worobey, Cox and Gill review calls the earlier cases in France and the UK "compelling" but contends that "early documentation of plausible cases is highly unlikely to indicate geographic origin." In a 2026 paper in Medical History, Douglas Gill and John Oxford reported further archival evidence of serious respiratory outbreaks in army hospitals in England and France before the first wave of the pandemic, argued that these were a herald wave, and described the Kansas hypothesis as having been "fatally undermined" by New York City epidemiological work led by Daniel Olson. That is the interpretation of authors who have long argued for a European origin, and it rests on archival hospital records. They add that surviving tissue slides from Étaples cannot yet be opened without destroying their contents.

Hypothesis 3: Chinese Labour Corps Theory

Canadian historian Mark Humphries published a third hypothesis in 2014 ("Paths of Infection: The First World War and the Origins of the 1918 Influenza Pandemic," War in History, January 2014), identifying a severe respiratory illness affecting the Chinese Labour Corps in 1917–18 — labourers transported across Canada and the North Atlantic to support Allied operations in France. Humphries argues that poorly documented illness in this population, combined with the routes of the Chinese Labour Corps across North America and to Europe, could represent an earlier emergence and a Chinese geographic origin.

The Chinese-origin theory has attracted significant criticism. Critics note that the underlying historical records are sparse and the respiratory illness described may not have been influenza. The hypothesis remains a minority position in the academic literature.

Genetic Phylogenetic Analysis

In 1997, molecular biologists Jeffery Taubenberger and Ann Reid and colleagues at the Armed Forces Institute of Pathology published the first genetic characterisation of the 1918 influenza virus, sequencing nine fragments of viral RNA from formalin-fixed lung tissue of a victim. In 1999 the group reported the complete sequence of the haemagglutinin gene, adding a frozen lung sample from a victim buried in permafrost in Alaska, and in 2005 Taubenberger and collaborators published the analysis of the complete 1918 H1N1 genome.

The phylogenetic analysis established that the 1918 virus was a novel H1N1 influenza A virus whose genes were avian-like; the 2005 analysis proposed that it was not a reassortant virus (like those of the 1957 and 1968 pandemics) but more likely an entirely avian-like virus that adapted to humans. A 2006 review in the CDC's Emerging Infectious Diseases concluded that historical and epidemiologic data are inadequate to identify the geographic origin and that phylogenetic analysis of the genome does not place the virus in any geographic context. The 2019 Worobey review points to separate, later (2014) phylogenetic work suggesting that most of the avian-like gene segments are of Western Hemisphere, probably North American, origin and that a reassortment event occurred in or around 1915, but calls this "by no means conclusive". The genetic data therefore describe the virus's evolutionary relationships but cannot pinpoint where on Earth it first emerged or amplified into pandemic form.

Why the Debate Persists

The origin of the 1918 pandemic remains scientifically contested for several reasons. First, the disease emerged during a world war in which the major belligerents suppressed unfavourable news, limiting the contemporaneous record that might have identified an early cluster. Second, influenza diagnosis in 1918 was clinical rather than laboratory-based; case records from 1916–18 cannot be retrospectively confirmed as 1918-strain influenza without preserved tissue samples, which are rare. Third, the pandemic's rapid global spread via wartime troop movements means that geographic dispersal happened so quickly that distinguishing the "first" cluster from the "first widely reported" cluster is methodologically difficult.

The Camp Funston hypothesis remains the most commonly cited in popular accounts. The 2019 Worobey review found strong contrary evidence against two of the three hypotheses, Haskell County and the Chinese Labour Corps, and cautioned that the Étaples cases, though compelling as early documentation, do not by themselves show where the pandemic began. The Chinese Labour Corps theory is contested but not dismissed.

Verdict

Unsubstantiated. The claim judged here is that the 1918 pandemic began at Camp Funston, Kansas. That has not been established. A large influenza outbreak at Camp Funston from 4 March 1918 is documented, and by Barry's account 24 of the 36 main US Army camps had influenza epidemics by the end of April, but the 2019 Worobey, Cox and Gill review argues that the Funston outbreak was mild and that New York City had already recorded very high influenza mortality, so it was probably not the first large outbreak of the pandemic virus. The more specific Haskell County version rests on a physician's report and local newspaper items, circumstantial travel links and no known surviving tissue samples, and its own proponent says the question cannot be settled with absolute certainty. The rival Étaples and Chinese Labour Corps hypotheses are also unproven. The scientific community regards the geographic origin as genuinely unknown. Two related points are not in dispute: the pandemic was caused by an H1N1 influenza A virus, and the 'Spanish flu' name reflects wartime press censorship rather than a Spanish origin.

What Would Change Our Verdict

• Recovery and genomic analysis of preserved tissue samples from early 1917–18 clusters in Étaples, China, or Kansas establishing clear phylogenetic precedence
• Discovery of contemporaneous clinical records with verified influenza diagnoses from a pre-March 1918 population that could be matched to the 1918 genome

Haskell County: A More Specific Kansas Claim

Some versions of the Kansas hypothesis go further than "Camp Funston." Historian John Barry's own version places the origin in Haskell County, in the southwest of the state. According to Barry, rural physician Dr. Loring Miner faced an unusually severe influenza epidemic in his practice in late January and early February 1918, roughly a month before Camp Funston's first documented case, and warned national public health officials in a report that Public Health Reports published in April 1918. Barry says this was the journal's only reference to influenza anywhere in the world in the first six months of 1918. Soldiers from the county reported to Camp Funston for training and were visited there by friends and family, and Barry argues that men exposed to the illness arrived at the camp between 26 February and 2 March 1918, just before the outbreak there began on 4 March. That would offer a plausible chain from an isolated rural cluster to the mass-mobilisation camp that shipped troops to Europe.

This more specific claim should not be overstated. Barry himself writes that it is impossible to answer the question of origin with absolute certainty. Little of Miner's own record survives beyond the few words of his Public Health Reports note, no tissue samples from the Haskell County cases are known, so the causative pathogen was never confirmed genetically, and the travel link to Funston rests on circumstantial contact patterns rather than a documented case-by-case chain. A 2019 critical review by Michael Worobey, Jim Cox and Douglas Gill, published in Evolution, Medicine, and Public Health, found strong contrary evidence to a Haskell County origin: the Camp Funston outbreak in March 1918 was mild, with many cases but few deaths, and it followed very high influenza mortality in New York City, so the virus was already circulating elsewhere. The authors wrote that the Kansas cases "make for a compelling story, but one that has perhaps left a stronger-than-deserved impression that they were the very first cases." They also cite earlier phylogenetic work pointing, inconclusively, to a Western Hemisphere, probably North American, source and a reassortment event around 1915, a broader and less specific claim than "it started in Haskell County."

The China Hypothesis Under Renewed Scrutiny

The Chinese Labour Corps theory has also accumulated both archival support and specific rebuttal since Mark Humphries' original 2014 research. Humphries, drawing on British and Canadian wartime archives, concluded that the 1918 flu most likely emerged first in China in the winter of 1917–18. According to a History.com account of his article, he found medical records indicating that more than 3,000 of the 25,000 Chinese Labour Corps workers transported across Canada from 1917, in sealed train cars with army guards, ended up in medical quarantine, many with flu-like symptoms, and he pointed to a mysterious respiratory disease that broke out in northern China in November 1917. Humphries himself acknowledged that "Only DNA testing of samples from these earlier outbreaks can truly confirm or deny the theory."

The 2019 Worobey review challenges this hypothesis. It cites work by Shanks showing that influenza cases among Chinese and Southeast Asian labourers and military recruits lagged, rather than led, cases among other groups in the same locales. It also argues that, even if the labourers travelled in sealed trains, it seems unlikely that the virus would not have initiated detectable spread in Canada had they really been the original hosts. As with Kansas, the China hypothesis remains a minority position with genuine archival evidence behind it but no genomic confirmation.

A Separate, Debunked Claim: The "Vaccine Caused It" Theory

A distinct and factually unsupported claim, unrelated to the three geographic-origin hypotheses above, holds that the pandemic itself was caused by an experimental bacterial meningitis vaccine trialled on soldiers at Camp Funston in late 1917 — not by an influenza virus at all. Full Fact noted a contemporary Journal of Experimental Medicine report of a "preliminary" trial and wider use of a meningitis vaccine following an outbreak in October and November 1917, but found no reason to believe it caused the later flu outbreak: meningitis and influenza are caused by unrelated kinds of microorganism, a bacterium versus a virus, and scientists have since recovered and sequenced the H1N1 influenza genome directly from preserved 1918 victim tissue. Epidemiologist Donald Burke told Reuters, as quoted by Full Fact, "There would be no way that a meningitis vaccine could contribute to starting a flu epidemic." This claim should not be conflated with the genuine, still-debated geographic-origin hypotheses discussed above — one is an open scientific question; the other has been directly refuted.