State of Debate on the Origins of AIDS
Backgrounder on the origins of AIDS debate, following the Royal Society meeting of September 2000 and its aftermath. (Originally written in recognition of World AIDS Day, December 2000, and updated on June 14, 2001.)
It is now twenty years since the new condition of AIDS was first recognised and reported in a medical journal (by two Los Angeles doctors), and World AIDS Day 2000 sees a tragic situation. According to the World Health Organization, over 60 million people have been infected with HIV since the start of the pandemic, of whom nearly 24 million have died.
By the year 2003, the AIDS pandemic will represent the worst outbreak of infectious disease the world has ever seen.
I have now been investigating the emergence and origins of AIDS for the last eleven years, and I still firmly believe that the likeliest explanation for why AIDS emerged when and where it did is that there was a connection with the trials in central Africa, in the late 1950s, of an experimental oral polio vaccine (OPV) called CHAT. My book on the subject of origin, "The River", was published in September 1999, and has sparked a considerable - and often acrimonious - debate in the scientific community.
A central tenet of the OPV hypothesis is that some batches of CHAT were prepared in the kidney cells of chimpanzees, which are now known to carry the direct ancestor of the AIDS pandemic virus, HIV-1. (During the fifties, polio vaccines were routinely prepared in the kidney cells of primates, but the choice of primates was left up to the vaccine producer.) It is known that the scientists who developed and administered CHAT in central Africa had a research camp in the Belgian Congo where approximately 250 chimpanzees were sacrificed between 1956 and 1958. For a number of reasons, not least the free availability of chimp kidneys to the CHAT researchers, I believe it likely that the kidneys of some of these chimps were used to make batches of CHAT vaccine. However, the vaccine's major developers, doctors Hilary Koprowski and Stanley Plotkin, deny this, saying they were using the chimps only to test the safety and efficacy of the vaccine.
However, 70% of the earliest AIDS cases in Africa, through 1980, come from the same towns and villages where CHAT vaccine was fed, as do nearly 85% of Africa's earliest samples of HIV-1. These constitute the earliest examples in the world of pandemic HIV and AIDS.
In September 2000, in response to "The River", the Royal Society in London convened a two-day conference to examine "The Origins of HIV and the AIDS Epidemic". The meeting was attended by over 300 scientists and reporters.
Although the main scientific supporter of the OPV theory, the renowned evolutionary biologist Bill Hamilton, had tragically died in March 2000, the remaining conference organisers declined to allow any additional main speakers on behalf of the OPV theory. However, they did allocate additional main speaker berths both to the makers of CHAT vaccine, and to the proponents of the main opposing hypothesis of origin - the "cut hunter/natural transfer hypothesis".
The imbalance of speakers, and the frankly partisan closing speech by co-organiser Robin Weiss, gave many attendees the impression that the meeting had been convened with the express intention of appearing to evaluate - and then dismissing - a hypothesis that the mainstream scientific community perceived as threatening.
Despite this, most scientific reports of the conference correctly concluded that no evidence had been presented to prove, or disprove, either theory. Indeed, the conference report in "Science" ended by quoting social scientist Brian Martin, who predicted: "Whatever happens at this conference, this controversy will continue".
The main evidence offered against the OPV theory in London was that seven samples of CHAT vaccine from the U.S. had been tested in independent labs, and found not to contain any HIV, or its monkey relative (SIV), or the DNA of the common chimpanzee. However, as I pointed out at the conference, all seven samples of CHAT were from batches prepared for use in Europe and the U.S., rather than for use in Africa. It is the batches of vaccine fed in Africa that are under suspicion, and the tests done thus far therefore make no impact, either way, on the OPV hypothesis
Shortly after the Royal Society meeting, there were three important new scientific announcements which offered support to the OPV theory.
First, American scientists revealed the remarkable information that the epithelium of the kidney is a hitherto unrecognised site of HIV-1 infection and replication. This is highly significant, because monkey kidney epithelium was the same medium used to prepare polio vaccines in the 1950s. [Journal of the American Society of Nephrology; 2000; 11; 2079-2087.]
Second, several hundred samples of HIV-1 from the Democratic Republic of Congo (the former Belgian Congo, where most of the CHAT trials were staged in the fifties) were analysed by Belgian, French and Congolese scientists. They concluded that there was a wider diversity of HIV-1 variants in the DRC than anywhere else, and suggested that the HIV-1 pandemic was indeed likely to have originated in this country. [Journal of Virology; 2000; 74; 10498-10507.]
Third, and perhaps most important, two Danish geneticists questioned the entire basis of the molecular dating of the HIV-1 epidemic by such as doctors Bette Korber and Paul Sharp. The latter scientists propose that the HIV-1 viruses seen today all stem back to a "most recent common ancestor" which existed in or around 1931, and many newspaper reports have focussed on their analysis, claiming (incorrectly) that it disproves the OPV hypothesis. In fact, the Danish geneticists propose that any molecular dating technique which fails to take into account recombination (a major method of retroviral evolution) is fundamentally flawed and unreliable. [Genetics; 2000; 156; 879-891. Nature Reviews Genetics; 2000; 1; 86. Molecular Biology and Evolution; 2000; 17; 1578-1579.]
Furthermore, one of the Danish researchers has proposed that the HIV-1 variation seen today could have been produced by just two chimpanzee SIVs which recombined in a kidney cell culture back in the fifties - exactly what the OPV hypothesis proposes.
In the last 18 months, I and other researchers have obtained important eye-witness testimony that kidneys were being extracted from chimpanzees in two different research centres in central Africa in the late fifties - and that the scientists involved were the same men and women who were working with CHAT vaccine. The accuracy of these testimonials is disputed by doctors Koprowski and Plotkin. However, with these testimonials, and with the important new scientific developments detailed above, many scientists are acknowledging (albeit often privately) that the evidence in favour of OPV hypothesis is accumulating.