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 Merino Sabin Merino Sabin Merino Zuloaga (; ; born 4 January 1992), known simply as Sabin, is a Spanish professional footballer who plays for CD Leganés on loan from Athletic Bilbao mainly as a left winger. Born in Urduliz, Biscay, Basque Country, Sabin graduated from Danok Bat CF's youth setup after spells at Athletic Bilbao's Lezama and American team Javanon FC. In the summer of 2011 he returned to the "Lions", and made his debut as a senior with the farm team in Tercera División. On 21 June 2013, Sabin was promoted to the reserves in Segunda División B. On 29