The Flu Has Been Making People Sick for At Least 500 Years

The 1918 flu pandemic gets all the headlines, but the malady is thought to have first appeared in the 16th century—and possibly earlier

Flu Docs
Doctors, army officers and reporters protect themselves during the 1918 pandemic. Bettmann/CORBIS

There’s no doubt about it—flu season is here. The CDC reported in late December that over half of America is experiencing a high rate of flu, and the numbers are expected to climb.

The offending strain this year—to blame for about 95 percent of cases—is H3N2, which is bad news for anyone hoping that the flu shot might guarantee an infection-free winter. Thanks to a virus mutation that occurred after the shot was manufactured, this year’s vaccine is believed to be only 33 percent effective at preventing the flu. (Though experts recommend that people—especially children, pregnant women, the disabled and the elderly—still get the vaccine, since some protection is still better than none at all.)

It is hard to talk about the flu without mentioning the most deadly of all flu pandemics—and the most deadly of all disease outbreaks in history—the 1918-1919 “Spanish flu.” The pandemic got its name from the erroneous assumption that the disease originated in Spain, but it killed up to 50 million people around the world.

Scientists believe the Spanish flu may actually  have first emerged in China, but there's not full agreement on that. What we’re surer of, however, is that the virus—or at least variations of it—has been around for hundreds of years.

The first flu pandemic is thought to have begun in the summer of 1510 and to have affected people in Africa and Europe before moving east through the Baltic States. This first flu didn't inflict a particularly high mortality rate, but fifty years later, the outbreak of 1557 was significantly more deadly. This round, the flu caused pleurisy and pneumonia-like symptoms in people from China to Europe; it's believed to have persisted for more than two years.

Seven other major pandemics—plus a rash of smaller epidemics confined to single cities, regions or countries—are thought to have occured prior to 1918, too. The peak of one pandemic that began in 1781 saw two-thirds of Rome’s population falling ill and over 30,000 new cases each day in St. Petersburg. (That starts to make last season's 53,470 confirmed flu cases seem more manageable.) 

Some medical historians say that the virus goes back even further than the 16th century and into antiquity. They point to a suspiciously flu-like illness mentioned in writings dating as far back as 412 B.C.  Reports of "a certain evil and unheard of cough" spreading through Europe in December 1173 cause some to believe flu pandemics have been around since the Middle Ages. (Other historians strongly caution that a lack of documentation means reliable evidence is lacking.)

All in all, over the past 500 years, some researchers believe that a flu epidemic has occurred approximately every 38 years. As the virus moves, it mutates, creating new strains and fresh epidemics despite human resistance and prevention efforts. How bad will this year’s season be? We can’t say for sure, but hey, at least you have the advantage of modern medicine to combat the symptoms—unlike your ancestors, who didn’t even have those nice lotioned tissues to comfort them.

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