Immediate initiation of Anti-Retroviral Therapy (ART) on diagnosis with HIV produces a 96% reduction in transmission to a non-infected partner. This is the remarkable finding of a large, multi-national, randomized clinical trial, begun in April 2005 by the HIV Prevention Trials Network (HPTN), and enrolling 1,760 HIV sero-discordant couples at 13 sites across Africa, Asia and the Americas.
As a condition of a couple’s enrolment, the HIV infected partner was in every case required to have a CD4 count of between 350 and 550 cells/mm3. The enrolled couples were randomized to two groups. In the “immediate ART group” the HIV infected partner initiated ART straight away; in the “delayed ART group” the HIV infected partner began ART when their CD4 count fell below 250 cells/mm3, or developed an AIDS-related illness.
The immediate ART group saw only one transmission to partner, as compared with 27 transmissions in the delayed ART group. Thus early ART appears to have reduced sexual transmission of HIV to the uninfected partner. The authors also claim that the benefits of early ART initiation extended to the infected partner, with a statistically significant reduction in the incidence of extra-pulmonary tuberculosis (3 in the immediate ART group as against 17 cases in the delayed ART group).
The clear message is therefore that interventions should link prevention with care efforts, since early initiation of ART has a decisive impact on transmission as well as benefits for the infected individual.
This trial (HPTN 052) is one of a number undertaken by the HIV Prevention Trials Network (HPTN). Largely funded by the US National Institute for Allergy and Infections (NIAID), the network embraces trials that deploy partnerships between researchers and communities across the world. HPTN trials investigate various aspects of HIV transmission. HPTN 043 demonstrated the effectiveness of community mobilization in extending the coverage of HIV testing services. HPTN 065, currently underway in the US, is looking at the impact on HIV transmission of increased knowledge of HIV status and linkage to care.