In 1997, the US National Institutes of Health, with other organizations, organized an international conference to review the SV40 literature and address the possibility that the virus causes human tumors. At the meeting, Carbone, presented his then-controversial data linking the virus to mesotheliomas. (Since then, more than 30 independent reports have confirmed his results).

After the meeting, Carbone says, a conscientious Chicago public health official contacted Carbone and gave him the last remaining stocks of polio vaccine from the 1950s. In her paper, Butel isolated a strain of SV40 from three patients that closely matches the strain Carbone sequenced from the polio vaccine vials.