evidence: A simian virus known as SV40 has been associated with a number of rare human cancers. This same virus contaminated the polio vaccine administered to 98 million Americans from 1955 to 1963. Federal health officials see little reason for concern. A growing cadre of medical researchers disagree [...] Others at the National Institutes of Health -- including some of the scientists who had been around at the time of the contamination scare -- were less receptive to the novel theory. They told Carbone that the last thing anyone wanted to hear was that the exalted polio vaccine was linked to cancer. Too much was at stake. Implicating a vaccine contaminant in cancer -- even if the contamination occurred some forty years ago -- might easily shake public confidence in vaccines in general. And besides, everyone knew that asbestos was the cause of mesothelioma.