Albert Bruce Sabin was an American medical researcher best known for having developed an oral polio vaccine. Like many researchers of his day, Sabin strongly disagreed with Salk’s approach of using injected, “killed” virus. Sabin believed that long-term immunity could only be achieved with a live, attenuated — or weakened — virus. Sabin was one of several polio researchers working to develop such an attenuated live virus vaccine. His was ready for testing on human volunteers by the mid-1950s.
Dr Sabin began his testing in 1954 with volunteers at a correctional facility in Chillicothe, Ohio. Later, countries such as the Soviet Union, Mexico and Czechoslovakia participated in large field trials. On 24 April 24 1960, the first community-wide immunisation program began in Cincinnati, Ohio. The success of these studies, trials and programs eventually assisted efforts in the US to switch from an inactivated vaccine to a live, attenuated one. Unlike the Salk vaccine, the Sabin vaccine provides intestinal immunity and provides secondary spread of the vaccine to unprotected contacts.
The Sabin oral poliovirus vaccine (OPV) was introduced in Australia in 1966. Until recently, the benefits of OPV use outweighed the very small risk of vaccine-associated paralytic poliomyelitis (VAPP) (statistically, this may occur in one child out of every 2.4 million OPV doses distributed). However, because of the rapid progress in global polio eradication and the diminished risk of wild virus associated disease, since November 2005 inactivated poliovirus vaccine (IPV) is now used for all doses of polio vaccine in Australia. The advantage of using IPV is that it cannot cause VAPP. However, OPV continues to be used in the countries where polio is endemic or the risk of importation and transmission is high. OPV is therefore recommended for global polio eradication activities in polio-endemic countries due to its ongoing advantages over IPV.
You can read more about Dr Sabin at this Wikipedia page.