Who developed the oral polio vaccine used in mass immunization campaigns?

Albert Sabin developed the oral polio vaccine used in mass immunization campaigns.

Sabin’s vaccine used live, weakened poliovirus strains that could be swallowed, usually on a sugar cube or in liquid. It became widely used internationally because oral delivery was inexpensive, practical, and easier to administer than injections during large campaigns. The vaccine was licensed in the early 1960s.

Jonas Salk developed the earlier inactivated polio vaccine, which contains killed virus and is injected. The two vaccines are often confused because both played major roles in reducing poliomyelitis. Oral vaccine can produce strong intestinal immunity and interrupt transmission, while its rare vaccine-derived complications have led many countries to shift toward inactivated vaccine schedules.

Sabin developed three attenuated strains corresponding to poliovirus types 1, 2, and 3. His work helped drive dramatic declines in polio cases worldwide and remains central to the history of global polio eradication efforts.