The Polio Vaccine Ends a Terror
A 1954 trial with nearly two million children, an April 1955 verdict of safe and effective, and an inventor who would not patent it
Quick facts
- Field trial
- 1954, almost two million children
- Results announced
- April 12, 1955, safe and ~90% effective
- Inventor
- Jonas Salk (killed-virus, injectable)
- Oral vaccine
- Albert Sabin's live-virus vaccine soon after
What happened
Polio was one of the most feared diseases of the early 20th century, paralyzing and killing children in seasonal epidemics. Jonas Salk developed a vaccine made from killed virus, and in 1954 a massive controlled field trial was launched, sponsored by the National Foundation for Infantile Paralysis, in which almost two million U.S. children between six and nine took part; more than 600,000 were injected with vaccine or placebo and the rest served as observed controls. On April 12, 1955, Thomas Francis, the trial's director and Salk's mentor, reported that the vaccine was safe, potent, and about 90 percent effective against paralytic polio. Salk became a national hero, and famously did not patent the vaccine. Soon after, Albert Sabin's live-virus oral polio vaccine, given in drops or on a sugar cube, replaced Salk's injectable vaccine in many parts of the world.
Why it matters
The polio vaccine lifted a specific dread from an entire generation of parents and became a template for mass immunization campaigns. It also stands as a landmark in the ethics of medical innovation as a public good: Salk's decision not to patent the vaccine, and the huge publicly organized trial that proved it, made polio prevention broadly available and helped drive the disease toward global elimination.
How we know
The 1954 field trial, its size, the April 12, 1955 announcement of the results, and Sabin's later oral vaccine are documented in institutional histories and in the peer-reviewed record analyzing the trial and its outcome.
Sources
- Science History Institute. Jonas Salk and Albert Bruce Sabin · General sourcesciencehistory.org · Cited as a "reference" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)
- BMJ (via PMC / U.S. National Library of Medicine). 'A calculated risk': the Salk polio vaccine field trials of 1954 · Peer-reviewed (author-declared)pmc.ncbi.nlm.nih.gov · Cited as a "journal" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)
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