The 1954 test of the polio vaccine involved 1.8 million children.
To test Jonas Salk's polio vaccine, the United States ran what was then the largest medical experiment in history. About 1.8 million children took part, many given either the vaccine or a harmless placebo. The results, announced in April 1955, launched mass vaccination and sent polio cases tumbling.
Polio was one of the most feared diseases in mid-century America. In the early 1950s there were more than 25,000 cases a year, and in 1952 about 58,000, with some 3,200 deaths. Earlier vaccine attempts had ended badly. In the 1930s, one live vaccine was linked to cases of paralysis and death, a rival killed-virus vaccine was withdrawn, and human vaccine work largely stopped for nearly twenty years.
A lucky accident helped break the deadlock. In 1948, in John Enders's lab in Boston, Thomas Weller found he had a few spare tubes of human tissue and, on the off chance, added poliovirus to them. The virus grew. Being able to cultivate polio in the lab transformed vaccine research and won Enders, Weller and Frederick Robbins a Nobel Prize in 1954. At the University of Pittsburgh, Jonas Salk's team developed a vaccine made from virus inactivated with formalin.
The field trial, led by Thomas Francis, began with about 4,000 children at a school in McLean, Virginia, and grew to 1.8 million children in 44 states. Roughly 440,000 received the vaccine, about 210,000 received a placebo of harmless culture fluid, and about 1.2 million were simply observed. On 12 April 1955 the results were announced: the vaccine was 60 to 70 per cent effective against type 1 poliovirus and over 90 per cent against the other two types. US cases fell from 35,000 in 1953 to 5,600 by 1957, and to 161 in 1961.
Success was not straightforward. Soon after the launch, some batches from Cutter Laboratories turned out not to have been properly inactivated; they caused about 260 cases of polio and 11 deaths, and led to government testing of every vaccine lot. Albert Sabin's oral vaccine, in commercial use from 1961, later became the mainstay of the global eradication campaign launched in 1988. Wild polio has since been eliminated from most of the world.
Source: Wikipedia — Polio vaccine · Text summarised from Wikipedia (CC BY-SA 4.0)
