SV40 contamination of polio vaccine

Not a claim but a documented contamination. Polio vaccine of that era was grown on rhesus macaque kidney cells, and those cells carried simian virus 40. Tens of millions of people in the United States, and many more elsewhere, received contaminated doses. SV40 was shown to induce tumours when injected into hamsters. Testing for it was required from 1961 and contaminated stocks were withdrawn, though existing lots were not recalled and continued to be administered.

Bernice Eddy — the same NIH scientist who had flagged the Cutter batches — identified a tumour-causing agent in the monkey cell substrate in 1959 and was moved off the work and stripped of her laboratory for saying so publicly. Maurice Hilleman and Ben Sweet formally characterised SV40 in 1960. The delay between identification and disclosure, and the institutional treatment of Eddy, are the documented parts most often left out of official retellings.

Accounts are deliberately not collected here. This entry documents a historical case rather than a circulating remedy.

SV40 DNA sequences have been detected in some human mesotheliomas and lymphomas by multiple laboratories, and not detected by others; contamination of laboratory reagents accounts for at least part of the discrepancy. Large cohort studies comparing people who received contaminated versus clean lots have not shown a clear excess of cancer. The Institute of Medicine reviewed the question in 2002 and concluded the evidence was inadequate to accept or reject a causal relationship — a formulation that has not changed much since. What is not in dispute is that a live monkey virus was distributed in a vaccine for eight years, that the agency knew before the public did, and that the scientist who raised it was punished.