Millions May Have Received Contaminated Polio Vaccine.

The article reports that a polio vaccine produced by at least one eastern European manufacturer was contaminated with a potentially cancer-causing virus as late as 1978. Introduced in 1954, the polio vaccine was a public health breakthrough that brought the spread of the paralytic virus to a screeching halt. To produce enough polio virus to make vaccine, manufacturers grew the virus in the kidney cells of rhesus monkeys. To prevent future contamination, vaccine producers switched to growing polio virus in SV40-resistant African green monkeys instead of rhesus monkeys.