Antiretroviral therapy for HIV prevention

Impact of treatment on prevention

ART lowers the concentration of HIV (also known as viral load) in the bloodstream and in genital secretions. Since viral load is the single greatest risk factor for all modes of HIV transmission, ART use decreases the risk that HIV will be transmitted from one person to another.

Proof of concept that antiretroviral drugs decrease HIV transmission comes from the prevention of mother to child transmission of HIV. Guidance also exists on the use of antiretroviral drugs for post-exposure prophylaxis to prevent HIV acquisition in HIV negative individuals, and research is ongoing on their use for pre-exposure prophylaxis.

Observational studies suggest that antiretroviral therapy reduces the sexual transmission of HIV in generalized epidemics, especially among sero-discordant couples. There is also growing evidence of the impact of ART on community-level HIV transmission, both, in generalized and concentrated epidemics including among injecting drug users. Most importantly ART is being provided as part of a package of prevention and treatment interventions and not in isolation.

Modelling efforts over the past decade have examined the effects of antiretroviral therapy on HIV prevention with varying results depending on the assumptions used in the model. A model by scientists from WHO published in 2008 suggested that expanding antiretroviral therapy to people with CD4 cell count <>

WHO has started the process of facilitating a dialogue among key partners to further evaluate the role of ART in HIV prevention or its use for individual and population level benefits and will guide the planning of research and keep partners abreast on its progress.