According to a Thursday report by US and Thai researchers, the risk of AIDS infection can be reduced by nearly one-third, as compared to placebo injections, by using an experimental vaccine that combines six "prime" and "booster" shots.

The reported findings were based on a six-year trial in Thailand, involving 16,000 heterosexual men and women volunteers who did not have an unusual risk of AIDS infection.

The researchers found the experimental AIDS vaccine - which combines ALVAC canary pox vaccine by Sanofi-Pasteurs and the failed HIV vaccine AIDSVAX - lowered the risk of HIV infection among the volunteers by 32 percent.

The vaccine is manufactured VaxGen, a San Francisco company, now owned by the nonprofit Global Solutions for Infectious Diseases.

Though the results of the study are fairly small, they are noteworthy for being the first positive results for an AIDS vaccine after almost twenty years of experimentation.

The measurable protective effects of the ALVAC-AIDSVAX vaccine would give virologists an insight into the happenings in the immune system of a person who is somewhat protected from HIV.

Commenting on the findings, Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, said: "Conceptually, we now know a vaccine is possible. Whether the vaccine is going to look anything like this one I don't know. But at least we know it can be done."