Thirty-five year mortality following receipt of SV40-contaminated polio vaccine during the neonatal period

Early poliovirus vaccines, both inactivated and live attenuated, were inadv ertently contaminated with simian virus 40 (SV40), a monkey virus known to be oncogenic for newborn hamsters. Although large epidemiologic studies hav e not identified an elevated cancer risk in persons who received SV40-conta minated vaccines, fragments of SV40 DNA have recently been identified in ce rtain human tumours. We report the follow-up of a cohort of 1073 persons, u nique because they received SV40-contaminated poliovirus vaccines as newbor ns in 1961-63. A previous report of the status of these subjects as of 1977 -79 identified 15 deaths, none due to cancer. The present study utilized th e National Death Index to identify deaths in the cohort for the years 1979- 96. Expected deaths were calculated from Cleveland area sex-, age-, race- a nd year-specific mortality rates. Increased mortality from all causes was n ot found. 4 deaths from cancer were found compared to 3.16 expected (P = 0. 77). However, 2 deaths from testicular cancer occurred, compared to 0.05 ex pected (P = 0.002), which may be a chance finding due to multiple compariso ns. There were 2 deaths due to leukaemia, at non-significant finding, and n o deaths due to tumours of the types putatively associated with SV40. Altho ugh these results are, for the most part, consistent with other negative ep idemiologic investigations of risks from SV40-contaminated vaccines, furthe r study of testicular cancer may be warranted, and it will be important to continue monitoring this cohort which is now reaching middle-age. (C) 2001 Cancer Research Campaign.