How the Original Polio Vaccine Was Made
During the 1950s, the inactivated polio vaccine created by Jonas Salk was made using rhesus monkeys that were infected with simian virus 40 (SV40), a monkey virus1 that was later linked to cancer in humans.2 From 1955 to 1963, hundreds of millions of people worldwide — in North and South America, Canada, Europe, Asia and… Read More »