AIDS researchers say they still have much work to do on a vaccine (疫苗) against HIV. But the first reports of some success have raised hopes. 1
The study was designed to test for two abilities. One was the ability of the vaccine to prevent HIV infections. The other was its ability to reduce the amount of virus in the blood of people who became infected during the study.
Volunteers received vaccinations over a period of six months and were tested for HIV for an additional three years. The study began in 2003. It was the largest AIDS vaccine trial yet. 2 Half received the vaccine. The other half received a placeho, an inactive substance (物质). The volunteers did not know which they were getting.
Seventy-four people in the placeho group became infected during the study. 3 Doctor Supachai Rerks-Ngarm, who led the study for the Thai Ministry of Public Health, called it a scientific breakthrough.
The National Institutes of Health also took part. Doctor Anthony Fauci at NIH called the findings an important step forward. 4 But he also said additional research was needed to better understand how the vaccine reduced the risk in those individuals.
The vaccine did not lower the amount of virus in the blood of volunteers who became infected during the study. The study was based on versions of HIV commonly found in Thailand. The volunteers received a combination of two vaccines. 5 The second, or booster, vaccine was developed by VaxGen. The nonprofit group Global Solution for Infectious Diseases now has rights to it.
Neither vaccine had been successful by itself when tested earlier. More detailed results of the study are expected to be presented at an AIDS vaccine conference in Paris next month.
|