Russian contribution to OPV.

Field trials and the first mass immunization campaign using Oral Poliomyelitis Vaccine (OPV) from the strains derived by Albert Sabin were carried out in the former U.S.S.R. in 1959 under the guidance of Mikhail Chumakov. The results obtained during these trials contributed greatly to the general acceptance of OPV as a safe and efficient preparation. Mechanisms responsible for the attenuated phenotype of the Sabin strains have long been studied in Russia. For the first time, recombination analysis was used for mapping genetic determinants of attenuation, which were found to reside largely in the 5' half of the Sabin strains RNA. It has been established that the phenotype effect of a subset of the major attenuating mutations is due to the impairment of the translation initiation.