Two polio vaccines are used throughout the world to combat polio. The first was invented by Jonas Salk, and first tested in 1952 and announced to the world by Salk on March 26, 1953. It consists of an injected dose of killed polio virus. Albert Sabin[?] produced a cheaper and more effective oral polio vaccine in 1962.
... and indigenous people of Tupi and Guarani language stock. Intermarriage between the Portuguese and indigenous people or slaves was common. Although the major European ...