Salk's Vaccine Declared Safe: Polio's Terror Ends

Church bells rang across the United States on April 12, 1955, the day Americans learned they would never again have to fear polio. Dr. Thomas Francis Jr. of the University of Michigan announced the results of the largest medical field trial in history: Jonas Salk's polio vaccine was safe, effective, and potent. The announcement, made to 500 scientists and reporters at the University of Michigan's Rackham Auditorium, was simultaneously broadcast to 54,000 physicians watching on closed-circuit television. Polio had terrorized American families for decades. The disease struck without warning, primarily in summer, paralyzing thousands of children each year. The epidemic of 1952 was the worst in American history, with nearly 58,000 cases, 3,145 deaths, and 21,269 left with some degree of paralysis. Public swimming pools closed, movie theaters emptied, and parents kept children indoors through the warmest months. President Roosevelt himself had been paralyzed by the disease in 1921. The field trial that validated Salk's vaccine was massive in scale. Beginning in April 1954, nearly 1.8 million children in 44 states participated, making it the largest peacetime mobilization of volunteers in American history. Some children received the vaccine; others received a placebo. Hundreds of thousands of parents, teachers, and healthcare workers volunteered to administer the injections and track results. The trial proved the vaccine was 80 to 90 percent effective against paralytic polio. Within hours of the announcement, the federal government licensed the vaccine for public use. Salk became a national hero overnight. When asked who owned the patent, he replied, "The people. Could you patent the sun?" Mandatory vaccination campaigns in subsequent years drove polio cases in the United States from tens of thousands annually to fewer than a hundred by the early 1960s. A disease that had shaped American childhood for half a century was effectively eradicated within a decade.