The 1918 Flu Was Called Spanish Because Spain Was the Only Country Allowed to Report It

The 1918 influenza pandemic almost certainly did not start in Spain. The first widely accepted U.S. case was an army cook named Albert Gitchell, who reported sick at Camp Funston in Kansas on March 4, 1918, with influenza symptoms. Cases had been turning up in nearby Haskell County since January. Within weeks the virus was loose among the U.S. military and on transport ships heading to Europe. There were earlier candidate outbreaks in northern France in late 1916 and in Étaples staging camps; the genuine geographic origin of the virus is still debated.

Its name came from politics, not epidemiology. The major belligerents in WWI — Britain, France, Germany, the United States — censored their press to suppress reporting on the outbreak, on the grounds that admitting an enormous epidemic in the ranks would damage morale. Neutral Spain had no such censorship. Spanish papers reported the epidemic openly, including the illness of King Alfonso XIII, and the rest of the world's coverage cited Spanish accounts. Spain itself ended up being blamed for what the rest of Europe had spread.

The death toll is one of the largest in human history and has never been pinned down precisely. Estimates have ranged from 17 million in a 2018 reassessment to as high as 100 million in John M. Barry's 2021 reanalysis. Roughly a third of the global population — about 500 million people — became infected. The pandemic had an unusual demographic curve. Where most flu deaths skew old and young, the 1918 strain killed disproportionately many adults between roughly 20 and 40, possibly because of an immune-system phenomenon called cytokine storm. India lost approximately 12 to 17 million people — around 5 percent of the population.