Contamination of poliovirus vaccines with simian virus 40 (1955-1963) and subsequent cancer rates

Context. - Poliovirus vaccine contaminated with live simian virus 40 (SV40), a macaque polyomavirus that is tumorigenic in rodents, was used extensively in the United States between 1955 and 1963. Simian virus 40 DNA has recently been detected in several rare human tumors, including ependymomas, osteosarcomas, and mesotheliomas. Objective. - To determine the risk of ependymoma, osteosarcoma, and mesothelioma among Americans who as children received SV40-contaminated poliovirus vaccine. Design. - Retrospective cohort study using data from the Surveillance, Epidemiology, and End Results program (1973-1993) and the Connecticut Tumor Registry (1950- 1969), as well as national mortality statistics (1947-1973). Setting. - United States. Participants. - Birth cohorts that were likely to have received SV40-contaminated poliovirus vaccine as infants, born 1956 through 1962 (60 811 730 person-years of observation); as children, born 1947 through 1952 (46 430 953 person-years); or that were unexposed, born 1964 through 1969 (44 959 979 person-years). Main Outcome Measures. - Relative risk (RR) of each cancer among exposed compared with unexposed birth cohorts. Results. - Age-specific cancer rates were generally low and were not significantly elevated in birth cohorts exposed to SV40-contaminated vaccine. Specifically, compared with the unexposed, the relative risk of ependymoma was not increased in the cohorts exposed as infants (RR, 1.06; 95% confidence interval [CI], 0.69-1.63), or as children (RR, 0.98; 95% CI, 0.57-1.69) nor did the exposed have an increased risk of all brain cancers. Osteosarcoma incidence also showed no relation to exposure as infants (RR, 0.87; 95% CI, 0.71-1.06) or children (RR, 0.85; 95% CI, 0.59-1.22). Last, mesotheliomas were not significantly associated with exposure, although the cohorts studied have not yet reached the age at which these tumors tend to occur. Conclusions. - After more than 30 years of follow-up, exposure to SV40- contaminated poliovirus vaccine was not associated with significantly increased rates of ependymomas and other brain cancers, osteosarcomas, or mesotheliomas in the United States.