title: Modeling the impact of HIV chemoprophylaxis strategies among men who have sex with men in the United States: HIV infections prevented and cost-effectiveness.
abstract: OBJECTIVE
  HIV chemoprophylaxis may be a future prevention strategy to help control the global epidemic of HIV/AIDS. Safety and efficacy trials of two agents are currently underway. We assess the expected number of HIV cases prevented and cost-effectiveness of a hypothetical HIV chemoprophylaxis program among men who have sex with men in a large US city.
  
  
  METHODS
  We developed a stochastic compartmental mathematical model using HIV/AIDS surveillance data to simulate the HIV epidemic and the impact of a 5-year chemoprophylaxis program under varying assumptions for epidemiological, behavioral, programmatic and cost parameters. We estimated program effectiveness and costs from the perspective of the US healthcare system compared with current HIV prevention practices. The main outcome measures were number of HIV infections prevented and incremental cost per quality-adjusted life-years saved.
  
  
  RESULTS
  A chemoprophylaxis program targeting 25% of high-risk men who have sex with men in New York City could prevent 780 (4%) to 4510 (23%) of the 19 510 HIV infections predicted to occur among all men who have sex with men in New York City in 5 years. More than half of prevented infections would be among those not taking chemoprophylaxis but who benefit from reduced HIV prevalence in the community. Under base-case assumptions, incremental cost was US$ 31 970 per quality-adjusted life-years saved. The program was cost-effective under most variations in efficacy, mechanism of protection and adherence.
  
  
  CONCLUSIONS
  HIV chemoprophylaxis among high-risk men who have sex with men in a major US city could prevent a significant number of HIV infections and be cost-effective.
authors.affiliation: Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London, UK. kamal.desai@imperial.ac.uk
authors.forename: Kamal
authors.initials: K
authors.lastname: Desai
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Sansom
authors.forename: Marta L
authors.initials: ML
authors.lastname: Ackers
authors.forename: Scott R
authors.initials: SR
authors.lastname: Stewart
authors.forename: H Irene
authors.initials: HI
authors.lastname: Hall
authors.forename: Dale J
authors.initials: DJ
authors.lastname: Hu
authors.forename: Rachel
authors.initials: R
authors.lastname: Sanders
authors.forename: Carol R
authors.initials: CR
authors.lastname: Scotton
authors.forename: Sada
authors.initials: S
authors.lastname: Soorapanth
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Boily
authors.forename: Geoffrey P
authors.initials: GP
authors.lastname: Garnett
authors.forename: Peter D
authors.initials: PD
authors.lastname: McElroy