The influenza outbreak of 1918 most likely began in Haskell County, Kansas. There are other theories that it began in China or Vietnam or France, but the United States is the most probable starting point, and there’s no earlier record than from Haskell County. The virus drifted from Haskell to a nearby military base, when it was still tame in comparison to what was to come. Not much more was said about the outbreak than a forgettable health notice about “influenza of severe type” the Midwest. From there, the virus worked its way through the ranks of soldiers and was then exported to other U.S. bases and the various war theaters across Afro-Eurasia. It came roaring back to America in the fall of 1918, in the previously mentioned New England cities.

What makes influenza dangerous is that it’s caused by viruses—not bacteria (a discovery that one of William Henry Welch’s many protégés made). It’s not quite an organism, but it’s not as lifeless as a chemical compound either. Its mission is to replicate, but it cannot do so apart from a host. It needs an organism’s cells in order to make thousands or even hundreds of thousands of self-copies.

What makes influenza viruses unique is that they are extremely infectious and competitive. Influenza viruses set off all the body’s warning bells, and the immune system sets up defenses based on what the body has already encountered. But a new variation of the virus is unknown to the body, and attacks a compromised and blind immune system. The body beats down any other viruses that might be present, and then, once all other familiar viruses have been eliminated, the new influenza virus begins its work. 

The United States was unprepared for the pandemic for a variety of reasons. One was Woodrow Wilson’s monitoring and manipulation of the press during World War I in order to make sure that the American people remained loyal to the war effort. George Creel—essentially Wilson’s minister of propaganda—kept a tight leash on information, created a spy network, and jailed dissenters who questioned the Wilson administration. There was a yawning chasm between the public and full, reliable information, even before the new influenza came on the scene.

Not only was there a propaganda machine running full tilt, there was a dearth of doctors and nurses in the United States. Thousands of nurses and doctors—among them the best and the brightest—were sent to Europe to support the war effort. Wilson said he wanted “the spirit of ruthless brutality to enter into every fibre of American life.” Even for civilians at home, life became austere. Excellent medical help was not readily available stateside. There were not nearly enough nurses to help civilians when the pandemic came crashing through North America.

What happened to the group of infected U.S. sailors that came back from war and were moved from Boston to Philadelphia became a tragically common occurrence throughout the country. The infected went to understaffed, crowded hospitals run by incompetent medical personnel. Within a matter of days, half of Philadelphia was infected, and some people were offering $100 bribes for nurses to admit them. But all the beds of all 31 hospitals in the Philadelphia area were full, so bribes fell on deaf and overworked ears.

The war engulfing the world contributed to these other realities to create the perfect storm that made the 1918 pandemic the deadliest in human history. The initial spring 1918 wave had been mild, but the fall outbreak in cities as far apart as Boston, Bombay, and Beijing constituted a vicious resurgence of the virus. It was as if the virus had gone dormant for a time, adapting, mutating, reassessing its moment to strike. When it did strike, it struck the world all at once. The attack was forceful enough to infect hundreds of millions of people around the globe. More than half the population of some cities were infected. A third of Japan was infected. Seven percent of Iran’s and Russia’s populations were wiped out. Some Pacific islands saw more than a fifth of their populations obliterated. In India alone, almost 20 million perished from the second wave of influenza. They couldn’t pull the corpses out of hospitals fast enough to make room for new patients.