Is receiving contaminated vaccine the only way to become infected with SV40?
Receiving contaminated vaccine is not the only way to become infected with SV40. Data suggest that SV40 has infected a small percentage of the human population independently of the polio vaccine. A study of German medical students found that 12% had SV40 antibodies in 1952, before the introduction of the polio vaccine (Geissler et al., 1985). Moreover, SV40 has been identified in people born in the 1980s and 1990s, well after the elimination of SV40 contamination from polio vaccines. This has led some to consider that the virus may spread from person-to-person. Some laboratory workers may have been exposed to SV40 (Horvath, 1965). It is not known whether people who live in countries with wild rhesus monkeys also could be exposed to SV40. Exactly how SV40 is transmitted among humans and how common it is among people in the U.S. population are unknown.
