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New AIDS Vaccine Show Promise

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New two-vaccine combination on trail in Thailand show promise as protection from AIDS…

The combination of two HIV vaccines on trail in Thailand have shown some success in protecting people from the autoimmune deficiency syndrome, AIDS. And in the hard-fought world of HIV research, that qualifies as a major breakthrough, says Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases:

For more than 20 years now, vaccine trials have essentially been failures,. Now its like we were groping down an unlit path, and a door has been opened. We can start asking some very important questions

The Thailand study involved combining two HIV vaccines already proven ineffective on their own. At the end of the three year study, people who receive both vaccines were 31 percent less likely to get HIV, compared to people who received a placebo.

aids vaccine New AIDS Vaccine Show Promise

But while this partial protection shows promise for the future of HIV and AIDS prevention, it has also raised the question as to why the vaccine only offers protection for some.

In the trial, around 8,000 volunteers received the vaccines, and an equal number received placebos. During the three years, 74 people in the placebo group were infected, compared to just 51 people from the vaccinated group.

Although the numbers are small, researchers say theyre statistically significant.

The two-vaccine drug consisted of a primer and a booster Alvac, containing a canarypox virus with three AIDS virus genes grafted onto it, and Aidsvax, originally made by Genentech, an engineered version of a protein found on the surface of the AIDS virus.

Researchers hoped this combination would teach the body to both recognize and destroy the HIV virus. Combining Alvac and Aidsvax came as a hunch to scientists who thought: If one was designed to create antibodies and the other to alert white blood cells, might they work together even if neither worked alone?

Experts admit there is still a long way to go before this promising research can benefit the public. HIV expert Adriano Boasso notes that few doctors would be comfortable administering vaccines that confer such marginal protection:

Nobody would be considering licensing a vaccine that is 30% effective, he says. Youd want to be aiming for 70-80% at least

The researchers also note that the vaccines were designed to combat the most common strain of the virus circulating in Southeast Asia, and say they might not work against the strains common in Africa, the United States, and elsewhere.

The results were announced this month by the Thai and American agencies that conducted the trial. Full details will be presented at next months AIDS Vaccine Conference.

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