What were the committees conclusions regarding SV40-contaminated polio vaccine and cancer?
Causality. The committee reviewed a number of studies involving groups of people who received polio vaccine during 1955-1963. These studies show no increased risk of cancer. However, the committee identified a number of limitations in the studies and therefore concluded that there is not enough evidence to accept or reject the hypothesis that SV40-containing polio vaccine causes cancer. Biological Mechanisms. The committee also reviewed research regarding the effects of SV40 on cultured cells and concluded that the biological evidence is strong that SV40 is a “transforming virus” (able to transform normal cells into abnormal, malignant cells). Similarly, the committee reviewed the existing data on the presence of SV40 in human cancer tumors. The committee pointed out that the detection of SV40 in tumors does not, by itself, demonstrate that the virus causes the tumors. They concluded that the biological evidence is of moderate strength that SV40 exposure could lead to cancer in humans.
