"Armed with the knowledge of different virus types of the same virus group, scientists worked on vaccines against all types to prevent all disease. By 1954, after decades of well-funded research, Jonas Salk and his team developed the first killed virus vaccine. It was a vaccine against polio, and it went against the dogmas established at the time: the vaccine had to contain live/attenuated virus, and that a dead virus could not cause an immune response. * Later, other researchers would test various vaccines, including vaccines for polio and measles, in institutionalized subjects. These tests, conducted by Salk, Hilary Koprowski, MD, and others, usually did not deliberately infect subjects with the disease agent."