title: Individual HIV Risk versus Population Impact of Risk Compensation after HIV Preexposure Prophylaxis Initiation among Men Who Have Sex with Men.
abstract: OBJECTIVE
  Risk compensation (RC) could reduce or offset the biological prevention benefits of HIV preexposure prophylaxis (PrEP) among those at substantial risk of infection, including men who have sex with men (MSM). We investigated the potential extent and causal mechanisms through which RC could impact HIV transmission at the population and individual levels.
  
  
  METHODS
  Using a stochastic network-based mathematical model of HIV transmission dynamics among MSM in the United States, we simulated RC as a reduction in the probability of condom use after initiating PrEP, with heterogeneity by PrEP adherence profiles and partnership type in which RC occurred. Outcomes were changes to population-level HIV incidence and individual-level acquisition risk.
  
  
  RESULTS
  When RC was limited to MSM highly/moderately adherent to PrEP, 100% RC (full replacement of condoms) resulted in a 2% relative decline in incidence compared to no RC, but an 8% relative increase in infection risk for MSM on PrEP. This resulted from confounding by indication: RC increased the number of MSM indicated for PrEP as a function of more condomless anal intercourse among men otherwise not indicated for PrEP; this led to an increased PrEP uptake and subsequent decline in incidence.
  
  
  CONCLUSIONS
  RC is unlikely to decrease the prevention impact of PrEP, and in some cases RC may be counterintuitively beneficial at the population level. This depended on PrEP uptake scaling with behavioral indications. Due to the increased acquisition risk associated with RC, however, clinicians should continue to support PrEP as a supplement rather than replacement of condoms.
authors.affiliation: Department of Epidemiology, Emory University, Atlanta, Georgia, United States of America.
authors.forename: Samuel M
authors.identifier: http://orcid.org/0000-0001-8840-105X
authors.initials: SM
authors.lastname: Jenness
authors.affiliation: Department of Epidemiology, Emory University, Atlanta, Georgia, United States of America.
authors.forename: Akshay
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Department of Anthropology, University of Washington, Seattle, Washington, United States of America.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Goodreau
authors.affiliation: Department of Epidemiology, Emory University, Atlanta, Georgia, United States of America.
authors.forename: Eli S
authors.initials: ES
authors.lastname: Rosenberg
authors.affiliation: Department of Epidemiology, Emory University, Atlanta, Georgia, United States of America.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Weiss
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Karen W
authors.initials: KW
authors.lastname: Hoover
authors.affiliation: Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Dawn K
authors.initials: DK
authors.lastname: Smith
authors.affiliation: Department of Epidemiology, Emory University, Atlanta, Georgia, United States of America.|Department of Global Health, Emory University, Atlanta, Georgia, United States of America.
authors.forename: Patrick
authors.initials: P
authors.lastname: Sullivan
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use*; D015658:HIV Infections / Q000453:epidemiology* / Q000517:prevention & control* / Q000635:transmission / Q000821:virology; D018451:Homosexuality, Male; D006801:Humans; D015994:Incidence; D008297:Male; D015233:Models, Statistical; D065129:Pre-Exposure Prophylaxis / Q000379:methods; D018570:Risk Assessment; D012747:Sexual Partners; D014481:United States / Q000453:epidemiology; D047568:Unsafe Sex
chemical_list: D019380:Anti-HIV Agents