Cold War tensions and the polio vaccine Sabin vaccine from the Soviet side. However other Soviet virologists argued that the Salk vaccine could be considered safe, since the Americans tested it on their own people. They considered that the Sabin vaccine must be potentially dangerous because the Americans did not wish to test it on their own society. The documented achievement of the Sabin-Chumakov collaboration eventually trumped the ideological differences of the Cold War. Their oral live-virus vaccine became federally licensed in 1962, and used for over three decades to help eliminate polio globally, replacing the Salk vaccine. Using these vaccines, the threat of polio remains only
Smallpox vaccine sheep were used. In the late 1940s and early 1950s, Leslie Collier, an English microbiologist working at the Lister Institute of Preventive Medicine, developed a method for producing a heat-stable freeze-dried vaccine in powdered form. Collier added 0.5% phenol to the vaccine to reduce the number of bacterial contaminants but the key stage was to add 5% peptone to the liquid vaccine before it was dispensed into ampoules. This protected the virus during the freeze drying process. After drying the ampoules were sealed under nitrogen. Like other vaccines, once reconstituted it became ineffective after 1–2 days at ambient temperatures. However,