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,
To determine the risk of ependymoma, osteosarcoma, and mesothelioma
among Americans who as children received SV40-contaminated poliovirus vaccine.
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).
Birth cohorts that were likely to have received SV40-contaminated poliovirus
vaccine as infants, born 1956 through 1962 (60811730 person-years of observation);
as children, born 1947 through 1952 (46430953 person-years); or that were
unexposed, born 1964 through 1969 (44959979 person-years).
Main Outcome Measures.—
Relative risk (RR) of each cancer among exposed compared with unexposed
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.
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