Coordinated by the National Foundation for Infantile Paralysis, the Salk vaccine field trial enrolled roughly 1.8 million children across the United States, Canada, and Finland in a double-blind study. Volunteers known as 'Polio Pioneers' lined up at schools to receive injections, marking a turning point in the fight against a disease that had paralyzed and killed thousands of children annually.
Polio terrified American parents in the 1950s. Each summer brought fresh outbreaks, filling hospital wards with children in iron lungs and leaving survivors with lifelong paralysis. Franklin D. Roosevelt's own struggle with the disease had already made it a national cause, funded by the March of Dimes campaign he helped popularize.
Jonas Salk, working at the University of Pittsburgh, had developed a killed-virus vaccine and tested it cautiously, first on monkeys, then on himself and his own family, before the massive public trial. The 1954 field trial was a monument of statistical rigor, designed by biostatistician Thomas Francis Jr. to use double-blind, placebo-controlled methods at unprecedented scale.
Children who participated wore buttons proclaiming them 'Polio Pioneers,' and many recalled the day for decades afterward, some with pride, some with the sting of the needle. The results, announced in April 1955, showed the vaccine was safe and effective, triggering nationwide celebration, church bells ringing, and a rush to vaccinate. Polio cases in the U.S. plummeted from tens of thousands annually to near zero within a decade.
Key people: Jonas Salk, Thomas Francis Jr., Franklin D. Roosevelt