On Mar. 28, 1953, Dr. Jonas Salk announced on CBS radio that his killed-virus polio vaccine was safe and effective, based on trials with 161 subjects (children at the D.T. Watson Home and Polk State School in Pennsylvania).

Convinced that basic immunologic principles could be applied successfully in practice, he and the other University of Pittsburgh researchers inoculated themselves and their family members. These early pilot studies successfully showed increased antibody levels, setting the stage for the massive 1954 national field trials. 

One year later, Salk began polio vaccine field trials, sponsored by the National Foundation for Infantile Paralysis (March of Dimes), among the largest and most publicized clinical trials ever undertaken. Across the United States, 623 972 schoolchildren were injected with vaccine or placebo, and more than a million others participated as “observed” controls. The results, announced in 1955, showed good statistical evidence that Jonas Salk’s killed virus preparation was 80-90% effective in preventing paralytic poliomyelitis.