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Thursday, April 26, 2001
ORIGIN OF AIDS
Vaccine theory of HIV debunked
By ROWAN HOOPER
A tempest that has been raging in the outwardly dignified world of academia is set to die down with the publication today of three papers in Nature and one in Science. The story -- about the origin of AIDS -- is one of intrigue, mystery and death. Mostly, however, it is about death.
AIDS is the world's leading infectious killer and the fourth-commonest cause of death. More than 30 million people have AIDS, and more than 19 million people, most of them Africans, have died of the disease.
In 1999, a British journalist, Edward Hooper, alleged that the AIDS pandemic is man-made, the result of the contamination of polio vaccines used in Africa in the late 1950s. Conspiracy theorists will tell you that, in fact, the CIA manufactured and spread HIV, but they'll have trouble backing up their claim. Hooper, however, spent more than nine years researching his theory, conducting more than 600 interviews with scientists and traveling widely across Africa. His arguments were published in his book "The River: A Journey Back to the Source of HIV and AIDS," which ran over 1,000 pages.
The polio-vaccine theory of the source of AIDS emerged in the early 1990s. Rolling Stone magazine writer Tom Curtis claimed in a 1992 article that the human immunodeficiency virus originated from the simian immunodeficiency virus of African green monkeys and that it had crossed to humans via polio vaccines made from monkeys. But the closest relative to HIV in nonhuman primates is SIV from chimpanzees, not from African green monkeys. So HIV must have crossed the species barrier from chimps to humans -- but how?
The Wistar Institute, based in Philadelphia, developed an oral polio vaccine in the 1950s and tested it in the Belgian Congo. Hooper alleged that the scientists, rushing to be the first to develop a polio vaccine, used chimpanzee kidneys to speed up production of the vaccine -- kidneys infected with SIV. The theory claimed that the manufacturer of the vaccine was responsible for accidently introducing HIV to humans.
The vaccine was administered to more than a million people between 1957 and 1960. What struck Hooper is the fact that 64 percent of the first AIDS cases in Africa came from the same villages in the former Belgian colonies of Congo, Rwanda and Burundi where the vaccinations took place. Moreover, all of the first HIV-positive blood samples from Africa came from nearby the vaccination sites. Surely, thought Hooper, this couldn't just be coincidence.
The late Oxford evolutionary biologist William Hamilton didn't think so either. The greatest British biologist since Darwin, Hamilton led an expedition to the Democratic Republic of Congo to research the claims. Tragically he contracted malaria in the jungle and died back in Britain. But the controversy created by Hooper's book, and the urging by Hamilton to analyze the DNA in the oral polio vaccine stocks, caused the Wistar Institute to release historical samples of the 1950s vaccine to independent labs for analysis. It is the results of these labs' studies that have now been published.
They show that the vaccine was made from rhesus monkeys, not chimpanzees, and that they totally lack DNA sequences from either chimps or HIV. Any arguments that vaccine-theory proponents might have had left are soundly quelled by the third of the Nature papers, by Andrew Rambaut and colleagues at the Department of Zoology, University of Oxford. Their analysis of the evolutionary relationships between the HIV subtypes show that HIV was present in a human host long before the vaccine trials were conducted in the Congo.
An author of another of today's Nature papers, Philippe Blancou of the Institut Pasteur in Paris, said, contrary to Hooper's claim, "This tight geographical and temporal association [between polio vaccination and the first AIDS cases] would seem to be coincidence."
At a meeting of the Royal Society in London last year, the preliminary results of these labs were released. The meeting itself had been postponed amid claims of coverups and conspiracies. The beleaguered Hooper rejected the results as "irrelevant," but as Robin Weiss of University College London says in an accompanying article in Nature, "That simply isn't so -- on the contrary, some beautiful facts have destroyed an ugly theory."
Hooper's theory has been blamed for generating undue fear of vaccinations among the public. And some doctors were angered because they felt that they were being blamed for causing AIDS. Since the polio-vaccine hypothesis has now been definitively laid to rest, it is to be hoped that the public's vaccination fear will subside.
But just what is the likely origin of AIDS?
Most researchers believe that a hunter butchered an SIV-infected chimp and contracted the virus through cuts on his hands. The "cut-hunter" theory then says that in the newly decolonized Africa, the virus had the chance to spread.
Despite the bitterness caused by Hooper and his book, there are several good consequences. We know much more about the relationships between the various HIV subtypes that have spread throughout the world and about their ancestors in other primates. But it has also highlighted the apocalyptic tragedy in Africa, where half of all 15-year-olds in Zimbabwe and South Africa will die of AIDS. In parts of Russia and China, HIV is tearing through the population, mainly due to the use of nonsterile needles. It was this practice, says Weiss, that allowed HIV to gain a foothold in Africa in the 1950s, and it is this practice that will infect huge parts of Asia unless something is done soon.
The ruling in a South African court last week offers some hope for AIDS sufferers. Pharmaceutical manufacturers abandoned their lawsuit against South African government laws aimed at getting cheaper anti-AIDS drugs to the poor. South Africa can now buy cheap drugs from countries like India and Thailand, although there is a danger that such drugs will be produced to less than stringent regulations.
E-mail Rowan Hooper at email@example.com