Mexico, and the Netherlands. The first industrial production and mass use of oral poliovirus vaccine (OPV) from Sabin strains was organized by Soviet scientist Mikhail Chumakov. This provided the critical impetus for allowing large-scale clinical trials of OPV in the United States in April 1960 on 180,000 Cincinnati school children. The mass immunization techniques that Sabin pioneered with his associates effectively eradicated polio in Cincinnati. Against considerable opposition from the March of Dimes Foundation, which supported use of Salk's relatively effective killed vaccine, Sabin prevailed on the Public Health Service (PHS) to license his three strains of vaccine. While the PHS stalled, the USSR sent millions of doses of the oral vaccine to places with polio epidemics, such as Japan. Sabin's first oral poliovirus vaccine (OPV), for use against type 1 polioviruses, was licensed in the United States in 1961. His vaccines for type 2 and type 3 polioviruses were licensed in 1962. At first, the monovalent poliovirus vaccines were administered together by being put on a sugar cube. In 1964, a single trivalent OPV containing all three viral serotypes was approved. Sabin's oral vaccine was easier to give than the earlier vaccine developed by Salk in 1954, and its effects lasted longer. The Sabin vaccine became the predominant method of vaccination against polio in the United States for the next three decades. It broke the chain of transmission of the virus and allowed for the possibility that polio might one day be eradicated. 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.needs references Philanthropy Sabin refused to patent his vaccine, waiving commercial exploitation by pharmaceutical industries, so that the low price would guarantee a more extensive spread of the treatment. From the development of his vaccine Sabin did not gain a penny, and continued to live on his salary as a professor. The Sabin Vaccine Institute was founded in 1993 to continue the work of developing and promoting vaccines. To commemorate Sabin's pioneering work, the institute annually awards the Albert B. Sabin Gold Medal in recognition of work in the field of vaccinology or a complementary field. Awards and recognition For the trivalent oral vaccine consisting of attenuated strains of all three types of the poliovirus, the president of the Supreme Soviet of the USSR awarded the highest civilian honour, the medal of