On Mar. 22, 1954, Dr. Jonas Salk’s team began giving inoculations of a commercially prepared vaccine to some 2,500 children from seven parochial schools in Pennsylvania.

These schools were St. Lawrence, St. Stephens, Holy Rosary, Sacred Heart, Resurrection, St. Basil and St. George. In 1954, Salk undertook a large-scale national study, enrolling over one million paediatric subjects.

The next year, on 12 April 1955, he announced the results: the vaccine was both safe and efficacious. Subsequent data showed that in 1955, there were approximately 29,000 cases of poliomyelitis in the US. Just two years after mass production and implementation of the newly developed vaccine, the infection rate plummeted to less than 6,000.

The Salk vaccine was quickly adopted nationwide, and by 1959, had reached about 90 countries. All inoculations given before this date were with a vaccine prepared in Salk’s lab at the University of Pittsburgh.

Polio was eliminated from North America by 1994 and in most countries worldwide shortly thereafter. Still, unlike smallpox, polio has not been entirely wiped out. As recently as 2013, Syria witnessed an outbreak, and the disease has now spread to some ten countries in Africa, Asia and the Middle East.