Polio was once the most feared disease in the U.S. Particularly in the 1940 and 50s, parents were sometimes fearful of letting their children even go outside. Each summer, polio seemed to strike without warning. Swimming pools, movie theaters, and Sunday school classes were closed. Almost 100 years passed from the first polio outbreak of any size in the U.S. through the development of a vaccine in 1955 to the eradication of the virus in the Americas in 1994.
