The Spanish flu outbreak, which lasted from 1918-1920, was the greatest natural disaster in humankind, infecting a third of the world population and claiming the lives of at least 50 million people. It was likely a strain of the virus similar to H1N1.

The flu was a further burden on a world in the throes of WW1. Notable people who died from the illness were French poet Apollinaire, Detroit Tigers owner Bill Yawkey and German political economist Max Weber.

This 1918 public-health awareness advertisement was the beginning of a consciousness-raising effort to warn Americans about the illness. It features the image of a sickly looking man being given a lot of space by his fellow citizens. The copy in full:

“Coughs and sneezes spread diseases. As dangerous as poison gas shells. Spread of Spanish Influenza menaces our war production. U.S. Public Service begins nationwide health campaign.”