Long-term use of oral poliovirus vaccine from Sabin strains in the Soviet Union.

Success in control of poliomyelitis in the USSR has been achieved after mass immunization with oral polio vaccine ( OPV ) manufactured from attenuated Sabin strains. Procedures for large-scale production of the OPV have been developed by Soviet researchers with the leadership of Chumakov and Smorodintsev , and the safety and efficacy of the vaccine have since been demonstrated. A mass immunization program was initiated in the USSR in 1959 and completed in 1960, covering 77.5 million people or 36.7% of the entire population. This immunization campaign resulted in a sharp decrease in the incidence of poliomyelitis: from 10.6 per 100,000 population in 1958 to 0.43 in 1963. Beginning in 1964 the incidence remained at a level of 0.01-0.1 per 100,000 population. At present the vaccination schedule consists of three basic vaccinations given to infants. Over 20 years of experience with OPV in the USSR has shown that this vaccine is a safe and efficient preparation.