Salk Polio Vaccine, Mahoney Strain

Jonas Salk first tested his polio vaccine on humans in July 1952 when he inoculated thirty children at the D. T. Watson Home for Crippled Children near Pittsburgh, Pennsylvania. These children had already had polio, so Salk's test was designed to prove that his vaccine would create a higher level of immunity than a natural infection. Salk also tested his vaccine on residents of the Polk State Home and on himself and members of his laboratory staff.

This vial contains residue of polio vaccine from these first tests. The polio virus exists in hundreds of different strains, all of which fall into three major types. A complete vaccine must contain a strain from each of these three types. However, the children at the Watson Home received only one type of vaccine matching the strain of their original polio infection. This vial is labeled for the Mahoney strain (Type I).

The Mahoney strain of the polio virus was isolated in 1941 from three children in the Mahoney family of Akron, Ohio. The children themselves were asymptomatic although they had been in contact with some serious cases of poliomyelitis.

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