Prevention of HIV-1 Infection with Early Antiretroviral Therapy
Cohen, M. S., Chen, Y. Q., McCauley, M., et al. New England Journal of Medicine (2011),365(11): 493–505.
This article reported expanded demographic and clinical information from the HIV Prevention Trials Network 052 trial, whose interim findings revealed a 96 percent reduction in the risk of HIV transmission among participants who had a CD4 count between 350 and 550 cells per cubic millimeter (cells/mm³) and received antiretroviral therapy (ART) upon entering the trial. Over half of the participating serodiscordant couples (54 percent, or 954 couples) were from Africa, 531 from Asia, and 278 from the Americas; 50 percent of the infected partners were men. Enrollees were randomized to receive ART immediately upon testing positive or to delay therapy until their CD4 counts dropped below 250 cells/mm³ or they acquired an AIDS-related illness. Of the total of 39 HIV transmission events, 35 occurred among participants in the delayed arm. A total of 61 percent of the 28 “linked” events occurred among individuals whose partner had a CD4 count greater than 350 cells/mm³, and 64 percent of HIV transmissions were from female to male partners. Individuals in the immediate treatment arm experienced a 41 percent lower risk of a clinical event than those in the delayed arm. According to the authors, the most likely mechanism in preventing HIV-1 transmission was sustained suppression of HIV-1 in genital secretions—the result of ART.