Level 2: Mid-level evidence
Observational studies have previously shown that antiretroviral therapy (ART) may reduce the transmission of HIV in serodiscordant couples.1 A new unblinded randomized trial suggests that early initiation of ART for the infected partner may reduce transmission more effectively than delaying ART until the CD4 count has fallen.2
A total of 1,763 stable heterosexual couples from nine countries (54% African participants) in which one partner was HIV-1-positive were randomized to early ART vs. delayed ART. Half of the infected partners were men, and the CD4 counts in the infected partners at the start of the trial ranged from 350-550 cells/mcL. The early group started therapy immediately. The delayed group began treatment following two consecutive tests showing CD4 count ≤250 cells/mcL or after the development of AIDS-related illness. All participants had counseling on risk reduction and condom use. Uninfected partners were tested for HIV every three months.
In median 1.7 years of follow-up, there were 39 total cases of HIV transmission, 28 of which were virologically linked to the infected partner. Of the linked transmissions, there was 1 case in the early ART group vs. 27 cases in the delayed ART group, with incidence rates of 0.1 vs. 1.7 per 100 person-years (HR=0.04, P<0.001). The infected partners were also followed for clinical events including death, World Health Organization stage 4 events, severe bacterial infections and pulmonary TB. Early ART was associated with a reduced incidence of clinical events (incidence rate 2.4 vs. 4 per 100 person-years (HR= 0.59, P=0.01).