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 Institute for Biological Studies becoming greener. The Salk Institute's open environment replete with empty space is symbolic of an open environment for creation, the symmetry stands for scientific precision, and submerging crevasses allow warm, natural light to enter the buildings like the intellectual light that leads to discovery. The contrast between balance and dynamic space manifests a pluralistic invitation for scientific study in structures developed to accommodate their respective functions as parts of a research facility. Although modern in appearance, it is essentially an isolated compound for individual and collaborative study, not unlike monasteries as sanctuaries for religious discovery, and they are thought to