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
For the Term of His Natural Life that he will fetch his lawyer to alter his will so that Richard receives no inheritance. When Richard leaves, he comes across a murder scene: his biological father, Lord Bellasis has been murdered, and Richard witnesses Sir Richard walking away from the scene of the crime. The police come and lock up Richard, who now gives his name as Rufus Dawes (which is used for the remainder of the book), for the murder of Lord Bellasis. Additionally, Sir Richard returns home and dies straight away, possibly of a heart-attack, without altering his will. Rufus Dawes/Richard Devine never finds this out.