CHAT Oral Polio Vaccine Was Not the Source of Human Immunodeficiency Virus Type 1 Group M for Humans

A book published in 1999 hypothesized that the scientists who worked with the CHAT type 1 attenuated poliomyelitis strain, tested in the former Belgian Congo in the late 1950s, had covertly prepared the vaccine in chimpanzee kidney cells contam-inated with a simian immunodeficiency virus, which evolved into human immunodeficiency virus type 1 group M. This article summarizes the results of the investigation conducted by the author to determine the legitimacy of the accusation. Testimony by eyewitnesses, historical documents of the time, epidemiological analysis, and analysis of ancillary phylogenetic, virological, and polymerase chain reaction data all indicate that this hypothesis is false. Poliomyelitis is rapidly disappearing from the world, thanks in large part to the widespread use of the oral polio vaccine (OPV) strains developed by Albert Sabin. The precursors of the Sabin strains were those developed by Hilary Koprowski, first at the Lederle Laboratories and then at the Wistar Institute in Phil-adelphia. The results of the first administration of OPV to humans were published by Koprowski et al. in 1952 [1] and concerned the TN strain, later identified as type 2 poliovirus. A type 1 strain, called SM, was reported in 1954 [2], and it