On Jun. 12, 1952 Dr. Jonas Salk went to the D. T. Watson Home for Crippled Children (now The Watson Institute) in Leetsdale, Pa., to begin taking blood samples from recently paralyzed polio patients and staff members in order to determine the types of antibodies each had.

The 1952 polio epidemic was the worst outbreak in U.S. history with nearly 58,000 cases reported that year with more than 3,000 deaths and leaving more than 21,000 people with mild to disabling paralysis. On April 12, 1955, the polio vaccine developed by Dr. Jonas Salk at the University of Pittsburgh was announced.