How many, if any, of the tens of millions of people worldwide given doses of polio vaccine contaminated by SV40 were infected by the virus? If people were infected, have some developed rare cancers as a result? And is SV40 now spreading from person to person?
More than 40 years after SV40 was first discovered, in polio vaccine, these crucial questions remain fiercely controversial. Those on both sides of the debate can point to seemingly strong evidence to support their views.
Several early studies suggest that SV40 did infect some of the people given contaminated vaccines. For instance, a 1964…
