Simian virus 40 (SV40), which contaminated polio vaccine widely distributed between 1955 and 1962, does not seem to have increased the likelihood of an exposed person developing the blood cancer non-Hodgkin lymphoma (NHL), according to a report from the National Cancer Institute. The new findings support those from another recent study that showed no link between use of another SV40-tainted vaccine and NHL, mesothelioma, or brain tumors. There had been concerns that the virus may promote these malignancies because SV40 DNA had been found in various tumor specimens.
