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
Jonas Salk as his primary interest. He said his desire was to help humankind in general rather than single patients. "It was the laboratory work, in particular, that gave new direction to his life." According to Salk: "My intention was to go to medical school, and then become a medical scientist. I did not intend to practice medicine, although in medical school, and in my internship, I did all the things that were necessary to qualify me in that regard. I had opportunities along the way to drop the idea of medicine and go into science. At one point at the end