What is the relationship between Simian Virus 40 (SV40) and polio?
SV40 is a monkey (simian) virus that infects several monkey species without making the animals sick. The virus can be found in the kidneys of these infected monkeys. Kidney cells from infected monkeys were used in the production of polio vaccines before the discovery of SV40 in 1960. As a result, some individuals who received those vaccines between 1955 and 1963 may have been exposed to SV40.