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
First of His Name reads: "Only slow by "Game of Thrones" standards, "First of His Name" demonstrates how carefully constructed this show has been since season one." Matt Fowler of "IGN" gave the episode a 9/10 writing that the episode "gave us a much-needed look back at some past events on the series." He highlighted the revelation that Littlefinger's actions "put the story of the entire series into motion." Erik Adams of "The A.V. Club" gave the episode an A and praised the writers for their focus on the female characters. First of His Name "First of His Name" is the fifth episode of