Albert Sabin a vaccine to prevent or mitigate the illness. The Sabin vaccine is an oral vaccine containing weakened forms of strains of polio viruses. In 1955, Salk's "killed" vaccine was released for use. It was effective in preventing most of the complications of polio, but did not prevent the initial intestinal infection. The Sabin vaccine is easier to give than the earlier vaccine developed by Salk in 1954, and its effects last longer. Sabin first tested his live attenuated oral vaccine at the Chillicothe Ohio Reformatory in late 1954. From 1956–1960, he worked with Russian colleagues to perfect the oral vaccine
Cold War tensions and the polio vaccine flew to Leningrad in June, 1956. As a result of a cooperation of Sabin and Chumakov in Leningrad, Sabin was able to test his attenuated vaccine when funding in America was declined. While Sabin was working behind the Iron Curtain, the Sabin-Chumakov vaccine was determined to be safe and effective. Cold War tensions caused Western scientists to refuse the reports from the Russians about the effectiveness of the Sabin vaccine. However, mass vaccinations of Sabin's vaccine spread throughout Eastern Europe from 1960–1963. Just as some Soviet virologists did not trust the Western Salk vaccine, Americans had similar reservations about the