Vaccine contamination by adventitious viruses in the cellular substrate has, of course, occurred before. In one instance, the discovery of SV40 in rhesus macaque kidney cultures (15) soon led to the adoption of cynomolgus macaque and later African green monkey (AGM) kidneys as the preferred substrate for polio vaccines. That was, perhaps, a near escape as AGMs are now known to frequently harbor a strain of simian immunodeficiency virus (SIV) that luckily does not appear to infect humans. Following the potential exposure of millions of polio vaccinees to SV40, no evidence was found of increased cancer incidence (16). More re- cently, it has been reported that SV40 is present in some human cancers (17). Cases include pediatric tumors in patients born long after SV40 was eliminated from polio vaccines. Ironically, it was the misguided attention of regulatory groups on hypothetical oncogenic DNA that led to vaccine contamination by adventitious oncogenic viruses in the first place. Fear of oncogenic DNA made tumor cell lines taboo as cellular substrates for vaccine produc- tion. Despite all we have learned about oncogenes and tumor suppressor genes in multistep progression to cancer, the possible trace of “oncogenic” DNA in vaccines prepared in established cell lines remained of greater concern to regulators than adventitious infec- tions in primary cells. It is high time to reevalu- ate the relative risks, so it is heartening that the Food and Drug Administration held a workshop last year to begin that process wwwnc cdc gov/eid/article/7/1/pdfs/70-0153.pdf
Posted on: Thu, 15 Aug 2013 03:02:47 +0000
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