title: Does ART prevent HIV transmission among MSM?
abstract: OBJECTIVE
  To review the evidence for antiretroviral 'treatment as prevention' for HIV transmission among MSM.
  
  
  METHODS
  We reviewed studies that assess the biological plausibility that virally suppressive antiretroviral therapy (ART) reduces HIV infectiousness via anal intercourse and the epidemiologic evidence of whether ART has played a role in attenuating HIV incidence among MSM.
  
  
  RESULTS
  Although ART treatment among MSM is likely to provide some preventive benefit, it is unknown whether it will reduce HIV infectiousness via anal intercourse to the same extent as via penile-vaginal intercourse. Additional research is needed on the pharmacokinetic properties of specific antiretroviral agents in the gastrointestinal tract. Estimates of risk behaviors and the incidence of HIV among MSM before and after the introduction and expansion of ART suggest that the population-level protective benefits of ART may be attenuated by a number of factors, most notably, continuing or increasing frequency of condomless anal intercourse and incidence of other sexually transmitted infections (STIs). Additional studies are needed on the impact of ART on HIV sexual risk behaviors and transmission among MSM outside of developed countries in North America, western Europe, and Australia.
  
  
  CONCLUSIONS
  The benefits of treatment as prevention for MSM are highly plausible, but not certain. In the face of these unknowns, treatment guidelines for earlier ART initiation should be considered within a combination prevention strategy that includes earlier diagnosis, expanded STI treatment, and structural and behavioral interventions.
authors.affiliation: Department of Medicine, University of North Carolina, Chapel Hill, USA.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Muessig
authors.forename: M Kumi
authors.initials: MK
authors.lastname: Smith
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Powers
authors.forename: Ying-Ru
authors.initials: YR
authors.lastname: Lo
authors.forename: David N
authors.initials: DN
authors.lastname: Burns
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Grulich
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Phillips
authors.forename: Myron S
authors.initials: MS
authors.lastname: Cohen
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use*; D001315:Australia / Q000453:epidemiology; D005060:Europe / Q000453:epidemiology; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission; D007722:Health Knowledge, Attitudes, Practice; D018451:Homosexuality, Male / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008297:Male; D009656:North America / Q000453:epidemiology; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D012725:Sexual Behavior / Q000706:statistics & numerical data*
chemical_list: D019380:Anti-HIV Agents