Hilary Koprowski he is chair of the department of radiation oncology at Christiana Hospital in Delaware. While at Lederle Laboratories, Koprowski created the world's first polio vaccine, based on an orally administered attenuated polio virus. In researching a potential polio vaccine, he had focused on live viruses that were attenuated (rendered non-virulent) rather than on killed viruses (the latter became the basis for the injected vaccine subsequently developed by Jonas Salk). Koprowski viewed the live vaccine as more powerful, since it entered the intestinal tract directly and could provide lifelong immunity, whereas the Salk vaccine required booster shots. Also, administering a vaccine
Jonas Salk it came into use in 1955. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Salk preferred not to have his career as a scientist affected by too much personal attention, as he had always tried to remain independent and private in his research and life, but this proved to be impossible. "Young man, a great tragedy has befallen you—you've lost your anonymity", the television personality Ed Murrow said to Salk shortly after the onslaught of media attention. When Murrow asked him, "Who owns this patent?", Salk