Jonas Salk’s Poliovaccine

13 April 2005

Yesterday was the 50th anniversary of the licensing of the first vaccine against poliomyelitis, the inactivated poliovaccine (IPV) developed by Jonas Salk.

On 12 April 1955, the results of the clinical trial of IPV were announced. The trial, supported by the National Foundation for Infantile Paralysis (NFIP) and organized by Thomas Francis of the University of Michigan, involved 1.8 million children. Francis and Salk announced that the vaccine was safe and effective; later that day five pharmaceutical companies were granted licenses to produce the vaccine.

From 1955 to 1962, 400 million doses of IPV were distributed in the U.S. The incidence of poliomyelitis was reduced from about 20,000 cases per year to 2,500 cases per year. In 1961, Albert Sabin’s oral poliovaccine (OPV) was selected to replace IPV in the U.S. The use of OPV lead to the eradication of poliomyelitis caused by wild type virus in the U.S. by 1979. In 2000, OPV was replaced by IPV in the U.S.

The IPV clinical trial was a huge event in medical history, and the success of the vaccine was a relief to millions of people at risk for infection with poliovirus. While Salk was declared a hero, the important contributions of Thomas Francis in conducting the clinical trial must not be forgotten.