This Smithsonian National Museum of American History exhibit celebrates the 50th anniversary of effective vaccines to prevent polio. On April 12, 1955, Dr. Jonas Salk, a virologist working at the University of Pittsburgh with funding from the March of Dimes, announced his vaccine against the disease. In 1957, trials of Dr. Albert Sabin's vaccine began. Between 1955 and 1957, the incidence of polio...