In this review, we will discuss the potential of early highly active antiretroviral therapy (HAART) to reduce the sexual transmission of HIV on an individual and population level. We will focus on the biological plausibility and behavioural factors associated with HAART use and interventions that might influence such a strategy.
Empiric and phylogenetic studies support the view that recent HIV infection is a highly infectious disease stage. Evidence increasingly demonstrates that individuals on fully suppressive HAART are significantly less likely to transmit HIV to sexual partners and some even suggest that such individuals cannot transmit HIV. Changes in risk behaviour are associated with the availability of HAART but behavioural studies offer contradictory observations regarding the direction and magnitude of these changes. This in turn makes the intricate assumptions and therefore outcomes of many complex mathematical modelling studies less secure. Furthermore, there is evidence that it is those individuals with undiagnosed HIV infection who contribute significantly to onward sexual transmission.
At an individual level, HAART will reduce viral load and, therefore, infectiousness, although whether to zero or not remains controversial. At a population level, if recent infection and undiagnosed infections continue to drive onward transmission, earlier treatment will only alter the pandemic if accompanied by an improvement in diagnosing the undiagnosed and recognizing recent infection.
aHIV/GUM Research Department, Brighton and Sussex University Hospitals NHS Trust, Brighton, UK
bDepartment of Infection, University College London Medical School, UK
cCentre for Infections, Health Protection Agency, London, UK
Correspondence to Deenan Pillay, Centre for Virology (Bloomsbury), Windeyer Building, 46 Cleveland Street, London W1T 4JF, UK Tel: +44 20 7679 9482; fax: +44 20 7580 5896; e-mail: firstname.lastname@example.org