On Jun. 17, 1916, an official announcement of the existence of an epidemic polio infection was made in Brooklyn, New York. Over the course of that year, there were over 27,000 cases and more than 6,000 deaths due to polio in the United States, with over 2,000 deaths in New York City alone.

Epidemics worsened during the century: In 1952, a record 57,628 cases of polio were reported in the U.S.