OPV AIDS Hypothesis - Scientific Investigation

Scientific Investigation

The OPV AIDS hypothesis has been examined and criticized by members of the scientific and medical communities as being unsupported or directly contradicted by available data, and inconsistent with HIV epidemiology.

In an August 1992 letter published in Science, Koprowski himself repudiated the OPV AIDS hypothesis, pointing to multiple errors of fact in its assertions. In October 1992, Science ran a story titled "Panel Nixes Congo Vaccine as AIDS source," describing the findings of an independent panel which found each proposed step in the OPV-AIDS hypothesis "problematic". The story concluded:

...it can be stated with almost complete certainty that the large polio vaccine trial... was not the origin of AIDS.

The oldest confirmed sample of human tissue that shows the presence of HIV-1 is an archival sample of plasma collected from an anonymous donor in the city of Leopoldville, Belgian Congo (now Kinshasa) in 1959. Initial phylogenetic analyses, published in 1999, led the researchers to hypothesise that HIV-1 entered "into the African population not long before 1959."

In 2000, the Royal Society held a meeting to discuss data on the origin of AIDS; the OPV AIDS hypothesis was a central topic of discussion. At this meeting, three independent labs released the results of tests on the remaining stocks of Koprowski's vaccine, which Edward Hooper had demanded in The River. The tests confirmed Koprowski's contention that his vaccine was made from monkey, rather than chimpanzee, kidney, and found no evidence of SIV or HIV contamination. Additional epidemiologic and phylogenetic data was presented at the conference which undermined other aspects of the OPV AIDS hypothesis. According to a report in Science, Hooper "did not challenge the results; he simply dismissed them." Brian Martin, a proponent of the OPV AIDS hypothesis, argued at the conclusion of the conference that if other AIDS-origin hypotheses were scrutinized in such detail, they would prove equally unsatisfying.

In 2001, three articles published in Nature examined various aspects of the OPV-AIDS hypothesis, as did an article published in Science. In every case, the studies' findings argued strongly against any link between the polio vaccine and AIDS. The evidence cited included multiple independent studies that dated the introduction of HIV-1 to humans as occurring between 1915 and 1941, probably in the 1930s. These results were confirmed by a later study using samples from the 1960s that also found that the epidemic began between 1908 and 1930, and a study that showed that although recombination amongst viruses makes dating less precise, it does not significantly bias estimates in either direction (it does not introduce a systematic error).

The author of one of the studies, evolutionary biologist Edward Holmes of Oxford University, commented in light of the new evidence: "Hooper's evidence was always flimsy, and now it's untenable. It's time to move on." An accompanying editorial in Nature concluded:

The new data may not convince the hardened conspiracy theorist who thinks that contamination of OPV by chimpanzee virus was subsequently and deliberately covered up. But those of us who were formerly willing to give some credence to the OPV hypothesis will now consider that the matter has been laid to rest.

The possibility that chimpanzees found near Kisangani in the Democratic Republic of Congo (formerly Stanleyville) were, indirectly, the true source of HIV-1 was directly addressed in a 2004 study published in Nature. Here, the authors found that while SIV was present in chimpanzees in the area, the strain of SIV infecting these chimpanzees was phylogenetically distinct from all strains of HIV, providing direct evidence that these particular chimps were not the source of HIV in humans.

Edward Hooper responded to these studies by either denying their relevance to the OPV hypothesis, disputing their accuracy, or asserting the existence of a "large organised cover-up" or other conspiracy.