Economist Review

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Did a vaccine cause AIDS?

By Edward Hooper. Little, Brown; 1,104 pages; $34. Allen Lane; £25

A frozen sample in a Philadelphia lab could illuminate the origin of AIDS

Economist, 13 November 1999, pp. 3-4.

IT IS a shame that the The River is so long, because many readers will give up before they have sieved out the extraordinary things it has to say about the origins of AIDS and the unintended consequences of medical testing. Half-buried in its more than 1,100 pages are two important questions. One is why, in different places in Africa, and apparently within the space of a couple of decades, three separate viruses emerged which each produce the symptoms of AIDS. The second question is whether an American research institute really is as reluctant as Edward Hooper implies to organise tests that might provide vital missing evidence.

The theory advanced in this book by Mr Hooper, a former BBC Africa correspondent and United Nations official, is that AIDS was accidentally introduced during vaccine trials in the 1950s and 1960s. In particular, he suspects that the most prevalent form of AIDS - the sort caused by the virus family known as HIV-1 group M - was introduced into Africa by way of CHAT, a vaccine against polio. CHAT was developed during the 1950s at the Wistar Institute in Philadelphia by a researcher called Hilary Koprowski and then tested on animals in those parts of Congo, Rwanda and Burundi (all then under Belgian rule) where the AIDS epidemic among humans seems to have originated.

This explanation of the origin of AIDS is controversial, not because the science underlying it is implausible but because of a gap in the evidentiary chain. It seems likely from the genetic fingerprint of HIV-1 that it evolved from a chimpanzee virus. How this might have happened is not known for sure. But Mr Hooper suspects that one or more batches of CHAT were grown on tissue cultures made from chimpanzee kidneys. Moreover, he believes that there is a way to test this conjecture. At least one sample of the suspect batch of vaccine is still safely on ice in the Wistar Institute's freezers. He therefore thinks - and he is not alone in thinking - that this preserved sample should be tested to see if it contains HIV or its chimpanzee precursor. Were it to be convincingly shown that it did, there would for the first time be really strong evidence of how AIDS arose, or at least for how the illness caused by HIV-1 group M came about.

In preparing this book, Mr Hooper has shown great diligence. He has grappled with the scientific technicalities. He has travelled to many places and talked to many people. He has tried to tell the story of AIDS in the round, bringing in its many aspects, including scientific research, medical assistance in poor countries, the links between poverty and disease - not to mention the counter-arguments to his own thesis. But here lies a problem. Mr Hooper takes to task an earlier proponent of the polio-vaccine theory of AIDS, Louis Pascal, for refusing to shorten a manuscript to make it publishable. Would that he had followed his own sound advice. His book is too confusing a mixture of history, science, speculation and reportage. Nobody is interviewed without a personal description; tea cannot be brought in without a record of the biscuits that came too.

Tiresome as they are, these flaws of style and organisation do not blunt or bury Mr Hooper's fundamental challenge. The trail of evidence he uncovers is significant. Most batches of CHAT were grown on tissue taken from monkeys. But the links between vaccine workers and a chimpanzee-research station in the Belgian Congo are close enough for it to have been at least a possibility that chimpanzee kidneys were used as well. There is no documentary evidence that chimpanzee kidneys were used. But the written records of which primate species were used for which vaccine batches are far from perfect, as are the memories of those who took part in the experiments.

Anyone who thinks that well-meaning and responsible researchers would never have been so careless should perhaps remember the times. Polio was a big killer and crippler in its day, causing the same kind of concern as AIDS does now, and pressure to find a reliable vaccine was intense. The very ethics of experimentation on humans were lax. Trials were carried out in America on the babies of women prisoners and on mentally handicapped children in public institutions (this was excused on the ground that such children were at higher risk from polio because they played with each other's excrement). The biggest vaccine trials, however, were reserved for Africa where poor volunteers were in supply.

That the rarer HIV-2 form of AIDS and the extremely rare form caused by HIV-1 group O were transferred to people by vaccination, is more of a piggy-back theory on the main assertion connecting HIV-1 group M with CHAT. But it is equally plausible. HIV-2 is closely related to a virus in the sooty mangabey monkey. HIV-1 group O is probably another chimpanzee virus. The same arguments, mutatis mutandis - that infected kidneys were used in the preparation of trial vaccines - could be applied to both. Indeed, the chances that the near-simultaneous transfers from monkey and ape to man were just an unfortunate coincidence are reduced still further by the recent discovery of a fourth AIDS virus, dubbed HIV-1 group N.

In sum, this book offers a scientifically plausible story, a testable hypothesis and a challenge. The plausible story is that AIDS viruses jumped from African animals to humans. The testable hypothesis is that this happened on occasion when CHAT polio vaccines were grown on chimpanzee kidneys. The challenge is to the Wistar Institute to facilitate tests on its surviving CHAT samples. A spokesman for the institute says that it has always been willing to allow such tests but has not been able to find more than one laboratory willing to do so. To be sure of the result, it wants two institutions to carry out separate tests. Any volunteers?