Source: Vaccine Safety (CDC):
Cancer, Simian Virus 40 (SV40), and Polio Vaccine Fact Sheet
- SV40 is a virus found in some species of monkey.
- SV40 was discovered in 1960. Soon afterward, the virus was found in polio vaccine.
- More than 98 million Americans received one or more doses of polio vaccine from 1955 to 1963 when a proportion of vaccine was contaminated with SV40; it has been estimated that 10–30 million Americans could have received an SV40 contaminated dose of vaccine.
- SV40 virus has been found in certain types of cancer in humans, but it has not been determined that SV40 causes these cancers.
- The majority of scientific evidence suggests that SV40-contaminated vaccine did not cause cancer; however, some research results are conflicting and more studies are needed.
- Polio vaccines being used today do not contain SV40. All of the current evidence indicates that polio vaccines have been free of SV40 since 1963.