Cold War tensions and the polio vaccine polio vaccine. By the 1950, Jonas Salk had tested both live, attenuated polio vaccines and formaldehyde killed polio vaccines in monkeys and by 1952, began testing on humans. The killed vaccine was found to be effective, with proper filtration of the biological culture. A problem with this vaccine was the perception that to be adequately protected; a child had to get three Salk shots, properly spaced, and a recommended booster shot once a year, which was expensive. It should be noted however, that Jonas Salk, himself, has stated in interviews that this perception is not at all true. This vaccine
Jonas Salk the University of Michigan. Francis had recently joined the faculty of the medical school after working for the Rockefeller Foundation, where he had discovered the type B influenza virus. According to Bookchin, "the two-month stint in Francis's lab was Salk's first introduction to the world of virology—and he was hooked." After graduating from medical school, Salk began his residency at New York's prestigious Mount Sinai Hospital, where he again worked in Francis's laboratory. In 1947, Salk became ambitious for his own lab and was granted one at the University of Pittsburgh School of Medicine, but the lab was smaller than