In 1918, It was estimated that about 500 million people or one-third of the world’s population became infected with this virus. The number of deaths was estimated to be at least 50 million worldwide with about 675,000 occurring in the U.S.

Mortality was high in people younger than 5 years old, 20-40 years old, and 65 years and older. In all, between 500,000 and 700,000 Americans –civilians and soldiers– died from the influenza, more than were lost in World War I, II, and the Korean and Viet Nam wars combined.