Cold War tensions and the polio vaccine was the first polio vaccine to receive approval of the U.S. government, and was used until 1961 in America, when the Sabin vaccine was recommended to replace it. Albert Sabin, a virologist who publicly disagreed with Salk and his killed vaccine, worked on creating a vaccine with live, attenuated vaccines. Despite Cold War tensions, in January, 1956 Mikhail Chumakov, the director of Moscow's Polio Research Institute, his wife and colleague Marina Voroshilova, and Anatoli Smorodentsev, traveled to the U.S. in order to study the Salk vaccine and visited the laboratory of Albert Sabin. With the clearance of the FBI, Sabin
Albert Sabin to Sabin, as well as assuming the middle name Bruce. Sabin received a medical degree from New York University in 1931. He trained in internal medicine, pathology, and surgery at Bellevue Hospital in New York City from 1931–1933. In 1934, he conducted research at The Lister Institute for Preventive Medicine in England, then joined the Rockefeller Institute for Medical Research (now Rockefeller University). During this time, he developed an intense interest in research, especially in the area of infectious diseases. In 1939, he moved to Cincinnati Children's Hospital in Cincinnati, Ohio. During World War II, he was a lieutenant colonel