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
His Name Is Legs (Ladies and Gentlemen) and Me (Babe)", which closed former Beatle Ringo Starr's 1973 album "Ringo". In the lyrics to "His Name Is Legs", Harrison biographer Simon Leng recognises the same "nonsense word games" favoured by Monty Python. Leng comments that the latter's composition "The Lumberjack Song" particularly resonated with Harrison during this period, as he sought to challenge the public's perception of him as a Beatle, in the same way that Michael Palin's character in the Python song challenged the stereotypes associated with an "all-action" lumberjack. Harrison taped "His Name Is Legs (Ladies and Gentlemen)" during sessions for his 1974 album "Dark Horse",