Polio vaccine The results of the field trial were announced 12 April 1955 (the tenth anniversary of the death of President Franklin D. Roosevelt, whose paralytic illness was generally believed to have been caused by polio). The Salk vaccine had been 60–70% effective against PV1 (poliovirus type 1), over 90% effective against PV2 and PV3, and 94% effective against the development of bulbar polio. Soon after Salk's vaccine was licensed in 1955, children's vaccination campaigns were launched. In the U.S, following a mass immunization campaign promoted by the March of Dimes, the annual number of polio cases fell from 35,000 in 1953
Salk Hall served as a residence for students. Pitt remodeled it to house the School of Dental Medicine and School of Pharmacy in 1961-1962. The Salk Hall Annex, a major renovation and three-story addition designed by the architectural firm Deeter, Ritchey, and Sippel for the Dental School, was completed the Terrace Street side of the building in 1967 for a cost of over $5 million ($ million today). Today, it serves as a main entrance for Salk Hall and the dental clinics. A new $50.6 million ($ million today) addition and renovation to Salk Hall was announced in January 2010. It will