Poliomyelitis leading to large-scale trials in the then Belgian Congo and the vaccination of seven million children in Poland against serotypes PV1 and PV3 between 1958 and 1960. The second inactivated polio virus vaccine was developed in 1952 by Jonas Salk at the University of Pittsburgh, and announced to the world on 12 April 1955. The Salk vaccine, or inactivated poliovirus vaccine, is based on poliovirus grown in a type of monkey kidney tissue culture (vero cell line), which is chemically inactivated with formalin. After two doses of inactivated poliovirus vaccine (given by injection), 90 percent or more of individuals develop
Jonas Salk making money." That belongs "in the category of mink coats and Cadillacs—unnecessary", he said. In the years after Salk's discovery, many supporters, in particular the National Foundation, "helped him build his dream of a research complex for the investigation of biological phenomena 'from cell to society'." Called the Salk Institute for Biological Studies, it opened in 1963 in the San Diego neighborhood of La Jolla. Salk believed that the institution would help new and upcoming scientists along in their careers, as he said himself, "I thought how nice it would be if a place like this existed and I was