Vaccine Efficacy Trial Soldiers On

The U.S. Military HIV Research Program just announced that their ongoing HIV vaccine efficacy trial (RV144) has been cleared to continue after a review by the Data Safety Monitoring Board (DSMB). The trial involves 16,402 Thai participants at low risk of HIV infection. The vaccines being studied are the weakly immunogenic ALVAC vector made by Sanofi Pasteur and a protein booster called AIDSVAX (which is no longer being manufactured after failing two prior efficacy trials). The RV144 trial has been criticized extensively in the past by scientists and activists. The UPI story contains this slightly cryptic statement: "While the board found that the current level of research in the trial doesn't suggest a vaccine is imminent, it did rule that the trial would ultimately provide a definitive answer on the matter." Clearly, the vaccine is not showing a level of protective efficacy that would require stopping the trial prematurely. One concern about the study was that the incidence of HIV infection might be too low to provide a clear answer regarding the vaccine's efficacy. The UPI story makes it sound as if the DSMB is saying that the trial will, in fact, be able to definitively show that the ALVAC/AIDSVAX approach does not work.