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Researchers: AIDS Vaccine Cuts Infection for First Time

In a major scientific breakthrough researchers in Thailand say they have made progress in developing a vaccine for AIDS. A six-year trial working with volunteers showed that a combination of drugs reduced the risk of HIV infection.

More than 16,000 Thai men and women took part in the clinical trial of a vaccine to prevent HIV infection and lower the amount of the virus in the blood stream.

The trial, the largest the world has seen for an AIDS vaccine, showed a combination of existing drugs reduced the risk of HIV infection by more than 30 percent. It is the first vaccine to reduce infections.

Dr. Supachai Rerks-Ngarm of Thailand's Ministry of Public Health says the results are a scientifically credible breakthrough.

He says among the volunteers, 74 who received placebos became infected with HIV compared with 51 taking the vaccine.

Researchers from the U.S. Army, which sponsored the trial, says a combination of two drugs lowered the rate of HIV infection, an outcome scientists call a significant step forward in the search for a vaccine.

The U.S. Ambassador to Thailand, Eric John, said it raises hopes that drug combinations could be effective as a vaccine in the future.

"It affirms the concept that a vaccine is possible," he said. "The fact that there was a degree of efficacy for the study proves that there could be a combination of medicines out there that would provide an effective vaccine. So I think proving the possibility of a potential vaccine is the important step forward."

Other partners in the project include the Thai Ministry of Public Health, the group Global Solutions for Infectious Diseases and pharmaceutical company Sanofi Pasteur.

Alain Bouckenooghe, who heads Sanofi Pasteur's Asia-Pacific operations, says the trial follows past failures in other tests around the world.

"There is no doubt that the world of vaccinology needed positive news," he said. "Over the last few years there have been several setbacks. This is the first phase three trial that shows that an efficacious vaccine and a safe vaccine can be designed. It will require more work but this is definitely good encouragement."

He added that the vaccine does not help those already infected with the HIV virus. But Thai scientists say further studies will be done on the longer-term effects on HIV patients.

Since AIDS and HIV were identified in the 1980s, scientists around the world have sought a vaccine to prevent infection. Certain anti-retroviral drugs can prolong life for HIV carriers by years, but they are costly. Millions of patients in Africa and other parts of the developing world can not get the drugs.

More than five million people live with HIV in Asia, with some 380,000 people becoming infected each year. A similar number perish from AIDS. Infection rates are highest in Southeast Asia, although they appear to be declining in Cambodia, Burma and Thailand.

But infections in Indonesia, Pakistan and Vietnam have been growing rapidly in recent years. In Vietnam, the United Nations says the rate of infections doubled between 2000 and 2005.