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Experimental vaccine reduced the risk of infection by a third
Hope?
First vaccine discovered that prevents HIV infection
An experimental HIV vaccine that prevents infection has been discovered, raising hopes of a major breakthrough in the fight against AIDS, in what was described as "an historic milestone".
16,000 Thai volunteers took part in the world's largest AIDS vaccine trial, sponsored by the US army and the National Institute of Allergy and Infectious Diseases. All were HIV-negative men and women aged between 18 and 30 at average risk of being infected. Half of them were given a placebo, and the other half a combination of two earlier, but unsuccessful, vaccines.
The new vaccine reduced the risk of HIV infection by a third. Colonel Jerome Kim, one of the leaders of the $105m study for the US army, said it was "the first evidence that we could have a safe and effective preventive vaccine".
Prior to this breakthrough, scientists had begun to believe that a successful vaccine might not be achievable after recent failures in the field. Dr Anthony Fauci, the National Institute's director, cautioned that it was "not the end of the road", but added: "It gives me cautious optimism about the possibility of improving this result. This is something that we can do."
It was stressed that the study used strains of HIV common in Thailand, and it was not known whether the new vaccine would work elsewhere in the world. The study was conducted in Thailand because US army scientists' key research work in isolating virus strains at the beginning of the AIDS epidemic there had provided vaccine makers with crucial genetic information.
Dr Richard Horton, editor of the Lancet, said: "This result is tantalisingly encouraging. The numbers are small and the difference may have been due to chance, but this finding is the first positive news in the AIDS vaccine field for a decade. We should be cautious, but hopeful. The discovery needs urgent replication and investigation."
The AIDS Vaccine Advocacy Coalition, an international group working to develop a vaccine, described the trial as "an historic milestone". Its executive director, Mitchell Warren, said: "There is little doubt that this finding will energise and redirect the AIDS vaccine field."
