Jonas Salk is credited with developing the first successful polio vaccine. In the early 1950s, Salk, an American medical researcher, created an inactivated polio vaccine (IPV) that effectively prevented the disease, which had caused widespread panic and paralyzed thousands of children annually. Salk’s vaccine was first tested in 1954 and proven safe and effective in protecting against poliomyelitis, a severe viral infection. The widespread use of Salk's vaccine led to a dramatic decline in polio cases, and his work is regarded as a major public health achievement. Salk chose not to patent the vaccine, believing it should be accessible to all, further solidifying his legacy.