When Was the Polio Vaccine Developed?

Poliomyelitis terrorised the world in the early 20th century, paralysing hundreds of thousands of children annually. The 1952 US epidemic alone caused nearly 58,000 cases and 3,145 deaths. Jonas Salk at the University of Pittsburgh developed an inactivated (killed) vaccine, which was tested in the largest medical trial in history: 1.8 million children ("Polio Pioneers") participated in 1954. On 12 April 1955, the trial results were announced: the vaccine was 80-90% effective. Salk famously refused to patent it, saying "Could you patent the sun?" Albert Sabin developed an oral live-attenuated vaccine (OPV), licensed in 1961, which was cheaper, easier to administer (sugar cube), and provided intestinal immunity that helped stop transmission. The Global Polio Eradication Initiative (launched 1988) has reduced polio cases by over 99.99%, from 350,000 cases per year to fewer than 100 (in just 2 countries as of 2024: Pakistan and Afghanistan).