Could the flu pandemic of 1918 really have started in Spain?

Investigation suggests that a second, deadly version of virus may have gestated in Madrid

Javier Sampedro
US soldiers suffering from Spanish flu in 1918 in Langres, France.
US soldiers suffering from Spanish flu in 1918 in Langres, France.age fotostock

Did the so-called “Spanish flu,” an epidemic that killed more than 50 million people worldwide between 1918 and 1919, really start in Spain? For almost a century Spaniards have either borne this mark of shame with resignation, wearily telling the world that it had to start somewhere, or have put the blame on neighboring France.

A new study by Spanish and US scientists points out that the pandemic was dubbed “Spanish Influenza” by the world because the press in Spain widely reported the outbreak in its early stages between May and June of 1918. Spain was not involved in World War I, and its media had no restrictions, while the main European nations and the United States, embroiled in the conflict, censored all news relating to the pandemic for fear of a decline in troop morale.

Spain was not involved in World War I, and its media had no restrictions when reporting on the outbreak

That said, the team of researchers, from the University of the Basque Country, Madrid’s Complutense University, and the Bethesda National Institutes of Health, as well as Arizona State University, are not ruling out the possibility that the pandemic may have originated in Spain. The paper, published in BMC Infectious Diseases, is the most detailed study of Spanish flu ever carried out, and establishes that Spain was certainly very badly hit by the pandemic, and that Spanish cities were definitely early sources of the virus.

A microscopic view of the flu virus.
A microscopic view of the flu virus.

As yet, there is no incontrovertible evidence that the virus emerged in Spain, although some of the authors believe it may well have. Antón Erkoreka, the director of the Basque Museum of the History of Medicine, says that such a hypothesis is perfectly possible, “but it has yet to be proved: perhaps the newspapers were right when they called it Spanish flu.”

In fact, the accepted version of events traces the first case of Spanish flu a long way from Spain, and before the first cases were reported in Spain: to March 4, 1918, at Camp Funston, Kansas, where US troops waiting to be sent to fight in Europe were stationed. Although the flu spread rapidly, it was no more lethal than any recorded in previous years. To begin with, the worst symptoms of the new epidemic were mild respiratory problems of the kind that still kill around half-a-million people every year around the planet.

Spain was very badly hit by the pandemic, and  Spanish cities were definitely early sources of the virus

But the virus that came to be known as Spanish flu had its own plans to enter the pages of infamy. At a certain point during the summer of 1918, it underwent a mutation, or a group of them, which converted it into the most efficient agent of death in history. Again, according to historical reconstructions used to this day, the first case of the second wave was not recorded in Spain, and dates to August 22, 1918, in the French port of Brest, used as the entry point for around half the US troops that had joined France and Britain in fighting Germany in April 1917.

“By April of 1918, the virus was in Europe,” says Erkoreka, “both among the troops as well as the civilian population; but this wave didn’t result in many deaths. Later though, the outbreak in Madrid that May was significant, both in terms of the high death rate, as well as the way that it affected people across class barriers: even King Alfonso came down with it between May and July,” he says, noting that the Spanish monarch did not belong to a high-risk group: he was aged 32, well-fed, and in good physical shape, but the virus was no respecter of palace walls.

In 1918, the virus underwent a mutation, converting it into the most efficient agent of death in history

The flu spread rapidly through Spain: the authors estimate that up to 237,000 people died out of a total population of 20 million. But by the autumn of that year, the mortality rate in Madrid had begun to fall in comparison to the provinces. This is an effect well understood by epidemiologists: the population of the capital had been exposed to the virus, and was by now immunized against its variants, but was now also able to help spread it. This process, say the researchers, shows that the virus had mutated during the summer. Those infected during the early stages were relatively fortunate, because they developed immunity to the second stage of the virus.

Previous studies of Spanish flu have generally discarded the idea that the pandemic originated in Spain, suggesting that it was already present in France in 1916, and that it was brought to Spain by unskilled Spanish and Portuguese laborers working in France. But these workers may well have taken the deadlier mutation of the virus back with them to France after the summer of 1918.

The Spanish-US team’s work, supported by a wealth of statistics, shows that just about every province in Spain was hit by the flu. There were three viral waves between January 1918 and June of 1919, moving from north to south, a process that can only partly be explained by socio-economic factors, says the team.

The pandemic’s long shadow


No epidemic of the last century has impacted on global health policy to the same extent as the Spanish flu of 1918; not even AIDS. An estimated 50 million people died in less than five years, a figure comparable only to the plagues of the Middle Ages. In some areas, even as remote as the Pacific islands of Western Samoa, 90 percent of the population was infected and 20 percent died in just two months.

The epidemic began a cycle that has been repeated, with lessening impact, in 1957 and 1968. The next was expected in the early 1990s, but has yet to present itself, confounding the epidemiologists. Who knows when it will hit?

The belief that every day that passes takes us closer to the next pandemic explains why the World Health Organization pays such close attention to flu outbreaks. Things have changed significantly since 1918, but this kind of deterministic thinking, along with probability calculations, are a basic tool for public health policy, and explain in large part the alerts of the last 15 years.

The shadow cast by the flu epidemic of 1918 was in the minds of WHO officials when they declared the 2009 H1N1 epidemic, a new virus that affected large numbers of people, including the young, in many countries and that took just two months to spread around the world. The 2005 H5N1 avian flu is still out there, and there is another, H7N9 in China that is on the rise.

The WHO’s decision to declare H1N1 an epidemic was widely criticized, and the organization’s mass vaccination campaigns were discredited: another victim of the Spanish flu.

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