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
Lee Salk his older brother. Salk attended the University of Michigan. Salk's published work investigated the effect of retirement on mortality, the effect of the mother's heartbeat on the newborn, and the relationship between adverse maternal and perinatal conditions and later self-destructive behavior. He was the author of eight books. Salk was married twice, first to Kerstin and then Mary Jane. He had two children from his first marriage, a son Eric and daughter Pia. Salk developed cancer and died in hospital in Manhattan at age 65 on May 2, 1992. Salk was a professor at Cornell University Medical Center. Lee Salk