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 April 12, 1955. It consists of an injected dose of killed polio virus. Thereafter, Albert Sabin produced an oral polio vaccine using live but weakened (attenuated) virus. Human trials of Sabin's vaccine began in 1957 and it was licensed in 1962. When the live-virus Sabin vaccine was developed, it spread in popularity for severa ...
Wikipedia - [full article]

Resources