Press Release

HIV Vaccine Study First to Show Some Effectiveness in Preventing HIV

24 September 2009—A Phase III clinical trial involving more than 16,000 adult volunteers in Thailand has demonstrated that an investigational HIV vaccine regimen was safe and modestly effective in preventing HIV infection. According to final results released by the trial sponsor, the U.S. Army Surgeon General, the prime boost combination of ALVAC? HIV and AIDSVAX? B/E  lowered the rate of HIV infection by 31.2% compared with placebo.  

In the final analysis, 74 placebo recipients became infected with HIV compared to 51 in the vaccine regimen arm. The efficacy result is considered statistically significant with a 95% confidence interval greater than zero. The vaccine regimen had no effect on the amount of virus in the blood of volunteers who became HIV-infected during the study.

This is the first time that an HIV vaccine candidate has reduced the risk of HIV infection in humans. This finding has important implications for the design of future HIV vaccines and how they are tested, however the public health benefits are unclear and require further study. In addition, the data show that the vaccine regimen is safe.

Collaborating partners on this study, referred to as RV144, include the U.S. Army, the Thai Ministry of Public Health, the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, Mahidol University, The Royal Thai Army, AFRIMS-Thai component, sanofi pasteur, and Global Solutions for Infectious Disease (GSID). The collaborators are already working with external experts to determine the need for additional studies on this vaccine regimen.

The U.S. Army Medical Component – Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), a special foreign activity of the Walter Reed Army Institute of Research (WRAIR) in Washington, D.C. and of the US Army Medical Research and Materiel Command (USAMRMC), helped to execute the trial in Thailand on behalf of the Sponsor.  With enthusiastic support from the US Ambassador to Thailand, this successful vaccine trial is another example of long–standing, productive collaboration between US and Thai military and civilian scientists to conduct basic and applied research on infectious diseases of global health and military importance.  

The U.S. Army would like to thank the more than 16,000 Thai men and women who consented to participate in this trial and the efforts of the Thai Ministry of Public Health and all collaborators for their hard work in achieving this important milestone.


Phase III HIV Vaccine Trial Background

The Thai Phase III clinical vaccine trial (RV 144) tested a prime boost vaccine strategy that combined two vaccines based on strains (subtypes) of HIV that circulate in Thailand. The first, or “prime” vaccine, known as ALVAC HIV, was developed by sanofi pasteur and the booster vaccine, AIDSVAX B/E, was originally developed by VaxGen and is now licensed to Global Solutions for Infectious Diseases.

The study, which began in 2003, was designed to test the vaccine strategy’s ability to prevent HIV infection, as well as its ability to reduce the amount of HIV in the blood of those who became infected after they enrolled in the study.

More than 16,000 HIV-negative men and women between the ages of 18 to 30 participated in the study; half of these participants received the prime-boost vaccine regimen and half received placebo. Volunteers received vaccinations over the course of six months, and were followed for an additional three years. Before agreeing to participate, all volunteers were informed of the potential risks associated with receiving the experimental vaccine regimen used in this study and consented to participate in the study. Volunteers continued to receive an HIV test every six months for three years following vaccination, in addition to counseling on how to prevent becoming infected with HIV.

For additional information regarding the trial, visit www.hivresearch.org

Media inquiries can be directed to Tawn Chatchavalvong of Hill &Knowlton, Thailand at +66 (2) 6273501 ext. 118 or tchatchavalvong@th.hillandknowlton.com.