The term POLIO CONQUERER refers to Jonas Salk, an American medical researcher and virologist who developed the first successful polio vaccine. He is credited with leading the fight against the crippling disease, which had caused thousands of deaths and disabilities in the United States and around the world. His breakthrough came in 1954 when he announced the successful development of the vaccine, which was made available to the public in 1955. The vaccine was made up of killed virus particles, and it was given the name Salk, after its creator.