Dr. Jonas Salk is known for creating the first successful polio vaccine. He developed the vaccine in the early 1950s after years of research, significantly reducing the incidence of polio, a disease that can cause paralysis or even death. Salk announced the success of the vaccine in 1955, and mass immunization programs followed soon after. Unlike later vaccines, Salk's was inactivated and required injections. His work is celebrated for its impact on public health, and he notably chose not to patent the vaccine so that it could be distributed widely and affordably.