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 talks continually about getting out of the limelight and back to his laboratory ... because of his genuine distaste for publicity, which he believes is inappropriate for a scientist." During a 1980 interview, 25 years later, he said, "It's as if I've been a public property ever since, having to respond to external, as well as internal, impulses. ... It's brought me enormous gratification, opened many opportunities, but at the same time placed many burdens on me. It altered my career, my relationships with colleagues; I am a public figure, no longer one of them." "If Salk the scientist sounds