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RV144 Trial

The Army-led Thai HIV vaccine efficacy trial, known as RV144, tested the “prime-boost” combination of two vaccines: ALVAC® HIV vaccine (the prime) and AIDSVAX® B/E vaccine (the boost). The vaccine combination was based on HIV strains that commonly circulate in Thailand.

The trial demonstrated that the prime-boost vaccine regimen was safe and modestly effective in preventing HIV infection, lowering the rate of HIV infection by 31.2 percent compared to placebo based on the modified intent-to-treat (mITT) population (n=51 vs. n=74, respectively; p=0.04).

This study results, announced by the Army in 2009, showed that a preventive HIV vaccine is possible, and the landmark trial continues to provide scientific direction to help guide vaccine development and testing. Since then, MHRP researchers—in collaboration with partners worldwide—have made substantive progress in understanding what it will take to develop a more efficacious HIV vaccine.

These study results showed that a preventive HIV vaccine is possible, and the landmark trial continues to provide scientific direction to help guide vaccine development and testing.  RV144 and its follow-on trials allowed researchers to discover correlates of risk, provided targets for optimizing vaccine boosting, and formed a foundation for three HIV vaccine candidates currently undergoing efficacy testing.

Progress since 2009
In April 2012, the New England Journal of Medicine (NEJM) published a paper co-authored by MHRP scientists that detailed clues to why the vaccine tested in the RV144 trial protected some volunteers. This unprecedented collaboration, led by researchers at Duke University and MHRP, brought together investigators from around the world to study those who became infected compared to those who did not. One finding was that immunoglobulin G antibodies that bind to the V1/V2 region of HIV’s envelope protein correlated with lower infection rates among those who were vaccinated. 

Next, scientists examined whether those vaccine-induced antibody responses selectively blocked certain HIV variants. They examined HIV genome sequences from 110 volunteers who participated in RV144, and who subsequently became infected with HIV. The findings, published in September 2012 in Nature, reinforced that antibodies directed at the V1V2 region reduced the risk of infection. “Taken together the work suggests that the Env-V2 region could be a critical target for future HIV vaccines,” noted Col. Jerome Kim, MHRP's former Principal Deputy Director and senior author on the study.

In the May 2012 issue of The Lancet Infectious Diseases, MHRP researchers reported that vaccine efficacy seemed to peak early—cumulative vaccine efficacy was estimated to be 60.5 percent (95 percent CI 22–80)—in the 12 months after initial vaccination, after which it declined quickly. This early, high protective immune response suggests an additional boost or other augmentation of immune response would improve efficacy.

RV144 is generating a wealth of scientific data through secondary studies with collaborators around the globe. 

Follow-up Clinical Research
MHRP began a small clinical study, RV305, in April 2012 in Thailand to evaluate re-boosting in volunteers who participated in the RV144 study. Findings from that study were published in 2017 and showed that boosting RV144 volunteers 6-8 years later with AIDSVAX B/E vaccine resulted in higher immune responses than were seen immediately after RV144. Another clinical study, RV306, began in September 2013 using the RV144 vaccine regimen to compare additional vaccine boosts and gather more immunogenicity data in 360 new volunteers.

A public-private collaborative team, called the Pox-Protein Public-Private Partnership (P5), initiated follow-up clinical studies using a similar vaccine regimen. For the subsequent efficacy study, HVTN 702, many variables were changed from RV144 in an effort to develop a public health tool for South Africa, where the HIV pandemic is most pervasive. Regrettably, the vaccine used in HVTN 702 was not effective and the study was stopped in early 2020.

Study Partners
The RV144 study was sponsored by the U.S. Army and conducted by the Thailand Ministry of Public Health. MHRP provided overall project leadership, and the Armed Forces Research Institute of Medical Sciences (AFRIMS) helped execute the trial. The study was made possible by an international collaboration involving numerous partners from the Thai and U.S. governments, private companies, non-profit organizations and more than 16,000 volunteers. It was supported by a cooperative agreement with the Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc.


RV144: A Phase III Trial of Aventis Pasteur Live Recombinant ALVAC-HIV(R) (vCP1521) Priming with VaxGen gp120 B/E (AIDSVAX(R) B/E) Boosting in HIV-uninfected Thai Adults 


 US Army Surgeon General 


Division of AIDS, National Institutes of Allergy and Infectious Diseases, NIH 

U.S. Army Medicacl Research and Materiel Command 


Rayong and Chon Buri Privinces, Thailand

47 health centers (screening and tracking)

8 clinical sites 

Vaccine Manufacturers 

Global Solutions for Infectious Diseases-AIDSVAX B/E (Global Solutions for Infectious Diseases (GSID) holds the intellectual property rights to AIDSVAX B/E originally developed and previously owned by VaxGen). 

sanofi-pasteur-ALVAC-HIV vCP1521

Study Execution

Department of Disease Control, Thai Ministry of Public Health (MOPH)

Vaccine Trials Centre, Faculty of Tropical Medicine Mahidol University

Data Management Unit, Faculty of Tropical Medicine, Mahidol University

Chon Buri and Rayong Provincial Chief Medical Offices, MOPH

Armed Forces Research Institute of Medical Scineces; Thai Componenet and U.S. Componenet (USAMC-AFRIMS)


U.S. Army Medical Materiel Development Activity, U.S. Army Medical Research and Materiel Command

It is important to note that a vaccine must be seen as part of a comprehensive approach to prevention of HIV infection. The true public health benefits of any vaccine, and particularly of an experimental vaccine that has not yet been licensed, can only be realized if vaccine recipients continue to control HIV risk-taking behavior.