HIV This Week

Cohen MS, Kaleebu P, Coates T. Prevention of the sexual transmission of HIV-1: preparing for success. J Int AIDS Soc. 2008;11(1):4.  

There are four opportunities for HIV prevention: before exposure, at the moment of exposure, immediately after exposure, and as secondary prevention focused on infected subjects. Until recently, most resources have been directed toward behavioural strategies aimed at preventing exposure entirely. Recognizing that these strategies are not enough to contain the epidemic, investigators are turning their attention to post-exposure prevention opportunities. There is increasing focus on the use of antiretroviral treatment-either systemic or topical (microbicides)- to prevent infection at the moment of exposure. Likewise, there is growing evidence that antiretroviral treatment of infected people could serve as prevention as well. A number of ongoing clinical trials will shed some light on the potential of these approaches. Above all, prevention of HIV requires decision-makers to focus resources on strategies that are most effective. Finally, treatment of HIV and prevention of HIV must be considered and deployed together.

Editors’ note: This excellent review of the prevention of sexual HIV transmission focuses on a menu of options driven by scientific results rather than ideology. Condoms and male circumcision have not reached their full prevention potential and the ecological evidence on the population-level benefits of antiretroviral treatment is mixed. Further, the very short time between HIV exposure, infection, and viral replication with seeding of reservoirs poses a major challenge for vaccine development. Pre-exposure prophylaxis gets antiretroviral protection on board before exposure to prevent infection at the time of exposure – it works for mother-to-child transmission so there are high hopes that it will enter the scientifically-validated combination prevention armamentarium for sexual transmission in coming years. Watch this space.