Background The efficacy of ARV treatment that achieves viral suppression in dramatically reducing HIV infectiousness is proven. What is less clear is the implications for the best use of treatment in programmes, how treatment should and could be scaled up and wheat the effectiveness of treatment use in programmes will be across populations.
Methods Review of observational data on the impact of treatment programmes on HIV incidence and deaths and mathematical models exploring the impact of existing and proposed programmes.
Results Mathematical models show that HIV treatment can reduce HIV incidence, but this reduction depends upon who is treated, the success of the programme maintaining viral suppression in those treated and on patterns of risk behaviour. Observations of the impact of treatment programmes on the spread of HV at a population level show mixed impacts with competing interpretations and implications for future programmatic development. Treatment guidelines emphasise the treatment of those who probably contribute least to onward transmission of HIV and more work is required to understand local epidemiology and design treatment programmes accordingly.
Conclusions Future, studies of the impact of treatment as prevention should concentrate on how to implement at scale treatment programmes and maximise reductions in incidence. Using HIV treatment as an HIV prevention intervention promises a major step forward in responding to the HIV pandemic, but taking success for granted could generate unsustainable programmes with perverse outcomes.
- HIV Prevention
- HIV treatment
- Mathematical modeling