
Ed Haslam | Dr. Mary’s Monkey, The Polio Vaccine, and Lee Harvey Oswald
Polio Vaccine Contamination, SV40 and Simian Virus Discovery
Researchers Sarah Stewart and Bernice Eddy discovered polyoma, a cancer-causing virus, in the late 1950s. This virus, later renamed Simian Virus 40 (SV40), was found to be native to the rhesus monkeys used to grow the Salk and Sabin polio vaccines. By the time the contamination was identified, approximately 100 million doses of the vaccine had already been administered to the American public.

