Origin of Aids may be a 1950s batch of polio drugs

Forty-year-old batches of polio vaccine are to be tested for HIV to discover if they were responsible for starting the Aids epidemic. Aids laboratories will try to establish whether HIV jumped from chimpanzees to humans as a result of using a vaccine that was made from chimp tissue.

Forty-year-old batches of polio vaccine are to be tested for HIV to discover if they were responsible for starting the Aids epidemic. Aids laboratories will try to establish whether HIV jumped from chimpanzees to humans as a result of using a vaccine that was made from chimp tissue.

The vaccine batches have been stored at the Wistar Institute in Philadelphia since the late 1950s, when they were used as part of the institute's vaccination programme in the Belgian Congo.

Clayton Buck, the chief administrative officer of the Wistar, said nine vaccine phials dating back to the period have been found in the institute's freezers, but only one is definitely known to have been used in the 1958-59 trial.

He said all nine samples will be tested by each of three separate Aids laboratories for HIV and the simian immunodeficiency virus (SIV), which naturally infects wild chimps. The scientists will also test the animal tissue used to make the vaccine to see whether it comes from chimps or another species of monkey. The names of the laboratories and scientists involved are being kept confidential, even among the participants, in the hope of an objective analysis.

Hilary Koprowski and Stanley Plotkin, the two Wistar scientists originally involved in developing the polio vaccine, claim that only rhesus macaque monkeys were used. If so, this would undermine the chimp hypothesis as macques come from Asia and are not naturally infected with SIV.

Professor Buck said he hoped to have results by May, when the Royal Society in London will host a conference on the origin of Aids.

Many Aids specialists have in the past dismissed the idea that polio vaccines used in Africa 40 years ago sparked the epidemic. However, recent research showing that the closest relative of HIV is a SIV that infects wild chimps has rekindled interest in the theory.

Ed Hooper, author of The River: A Journey Back to the Source of HIV and Aids, believes that chimpanzees were used in vaccine development and has produced strong, albeit circumstantial, evidence that this triggered the Aids epidemic in humans. However, the latest estimate of when chimp SIV might have jumped to humans suggests that it occurred more than 20 years before the Congo vaccine trials.