Salk Polio Vaccine, MEF-1 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 MEF-1 strain (Type II). The MEF-1 polio virus strain was originally isolated in 1942 from incidents of poliomyelitis occurring among the Middle East Forces of the British Army, in Cairo, Egypt.

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