Polio vaccine is usually provided in vials containing 10–20 doses of vaccine. A single dose of oral polio vaccine (usually two drops) contains 1,000,000 infectious units of Sabin 1 (effective against PV1), 100,000 infectious units of the Sabin 2 strain, and 600,000 infectious units of Sabin 3. The vaccine contains small traces of antibiotics—neomycin and streptomycin—but does not contain preservatives. In a generic sense, vaccination works by priming the immune system with an 'immunogen'. Stimulating immune response, by use of an infectious agent, is known as immunization. The development of immunity to polio efficiently blocks person-to-person transmission of wild poliovirus, thereby protecting
Albert Sabin humanitarian benefit. Indeed, it was not clear to many that the vaccine was an American one, financed by U.S. dollars, as it was not widely available to ordinary Americans. Sabin also developed vaccines against other viral diseases, including encephalitis and dengue. In addition, he investigated possible links between viruses and some forms of cancer. In 1983, Sabin developed calcification of the cervical spine, which caused paralysis and intense pain. Sabin revealed in a television interview that the experience had made him decide to spend the rest of his life working on alleviating pain. This condition was successfully treated by surgery