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
Jonas Salk artists have joined the scientists to achieve an understanding of man in all his physical, mental and spiritual complexity. Such interchanges might lead, he would hope, to a new and important school of thinkers he would designate as biophilosophers." Salk told his cousin, Joel Kassiday, at a meeting of the Congressional Clearinghouse on the Future on Capitol Hill in 1984 that he was optimistic that ways to prevent most human and animal diseases would eventually be developed. Salk said people must be prepared to take prudent risks, since "a risk-free society would become a dead-end society" without progress. Salk describes