Mikhail Chumakov Mikhail Chumakov Mikhail Petrovich Chumakov () (November 14, 1909 – June 11, 1993) was a Soviet microbiologist and virologist most famous for conducting pivotal large-scale clinical trials that led to licensing of the Oral Polio Vaccine (OPV) developed by Albert B. Sabin. Chumakov graduated in 1931 from Moscow State University Medical School that was later transformed into I.M. Sechenov Moscow Medical Academy. In 1937 Chumakov participated in a scientific expedition to Khabarovsk region of Soviet Far East that was led by Professor . Together with his colleagues he discovered the etiology of a new transmissible neurological disease called tick-borne encephalitis
Polio vaccine attenuate the Sabin 2 strain, and 10 substitutions are involved in attenuating the Sabin 3 strain. The primary attenuating factor common to all three Sabin vaccines is a mutation located in the virus's internal ribosome entry site, which alters stem-loop structures, and reduces the ability of poliovirus to translate its RNA template within the host cell. The attenuated poliovirus in the Sabin vaccine replicates very efficiently in the gut, the primary site of infection and replication, but is unable to replicate efficiently within nervous system tissue. In 1961, type 1 and 2 monovalent oral poliovirus vaccine (MOPV) was licensed, and