Robert McCollum, a viral researcher, has died, reports the New York Times. He was 85. McCollum was part of a team at Yale University in the 1950s that discovered that the polio virus circulated in the blood before entering the spinal column — a finding that paved the way for a vaccine, the Times notes. McCollum then studied hepatitis and was able to tell the difference between serum hepatitis from transfusions and infectious hepatitis.