title: Potential impact of early antiretroviral therapy on transmission.
abstract: OBJECTIVE
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: HIV/GUM Research Department, Brighton and Sussex University Hospitals NHS Trust, Brighton, UK.
authors.forename: David
authors.initials: D
authors.lastname: Pao
authors.forename: Deenan
authors.initials: D
authors.lastname: Pillay
authors.forename: Martin
authors.initials: M
authors.lastname: Fisher
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D005260:Female; D015658:HIV Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000517:prevention & control / Q000635:transmission*; D006801:Humans; D008297:Male
chemical_list: D019380:Anti-HIV Agents