Polio vaccine attenuated vaccine strains. In 1958, the National Institutes of Health created a special committee on live polio vaccines. The various vaccines were carefully evaluated for their ability to induce immunity to polio, while retaining a low incidence of neuropathogenicity in monkeys. Large-scale clinical trials performed in the Soviet Union in late 1950s to early 1960s by Mikhail Chumakov and his colleagues demonstrated safety and high efficacy of the vaccine. Based on these results, the Sabin strains were chosen for worldwide distribution. Fifty-seven nucleotide substitutions distinguish the attenuated Sabin 1 strain from its virulent parent (the Mahoney serotype), two nucleotide substitutions
Sabin of Bulgaria Pagan, but the emperor's words on behalf of the former monarch made little impression. Sabin passed the remainder of his life in exile. Sabin of Bulgaria Sabin () was the ruler of Bulgaria from 765 to 766. Some scholars think that Sabin was omitted from the Namelist of Bulgarian Rulers because he was a Slav, but his name could indicate Latin or even Iranian origins. He was related by marriage to Kormisosh, who was either a father-in-law or a brother-in-law of Sabin. Since the relation is by marriage, Sabin would not have actually belonged to the Vokil (=Ukil?) clan. Sabin