title: Acute HIV infection transmission among people who inject drugs in a mature epidemic setting.
abstract: Estimates for the contribution of transmission arising from acute HIV infections (AHIs) to overall HIV incidence vary significantly. Furthermore, little is known about AHI-attributable transmission among people who inject drugs (PWID), including the extent to which interventions targeting chronic infections (e.g. HAART as prevention) are limited by AHI transmission. Thus, we estimated the proportion of transmission events attributable to AHI within the mature HIV epidemic among PWID in New York City (NYC).
  
  
  
  Modeling study.
  
  
  
  We constructed an interactive sexual and injecting transmission network using an agent-based model simulating the HIV epidemic in NYC between 1996 and 2012. Using stochastic microsimulations, we cataloged transmission from PWID based on the disease stage of index agents to determine the proportion of infections transmitted during AHI (in primary analyses, assumed to last 3 months).
  
  
  
  Our calibrated model approximated the epidemiological features of the mature HIV epidemic in NYC between 1996 and 2012. Annual HIV incidence among PWID dropped from approximately 1.8% in 1996 to 0.7% in 2012. Over the 16-year period, AHI accounted for 4.9% (10th/90th percentile: 0.1-12.3%) of incident HIV cases among PWID. The annualized contribution of AHI increased over this period from 3.6% in 1996 to 5.9% in 2012.
  
  
  
  Our results suggest that, in mature epidemics such as NYC, between 3% and 6% of transmission events are attributable to AHI among PWID. Current HIV treatment as prevention strategies are unlikely to be substantially affected by AHI-attributable transmission among PWID populations in mature epidemic settings.
authors.affiliation: aDepartment of Epidemiology, Brown University School of Public Health, Providence, Rhode Island bFenway Health cBeth Israel Deaconess Medical Center dDepartment of Systems Biology, Harvard Medical School eBoston University School of Public Health, Boston, Massachusetts fNational Development and Research Institutes, New York, New York, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Escudero
authors.forename: Mark N
authors.initials: MN
authors.lastname: Lurie
authors.forename: Kenneth H
authors.initials: KH
authors.lastname: Mayer
authors.forename: Caleb
authors.initials: C
authors.lastname: Weinreb
authors.forename: Maximilian
authors.initials: M
authors.lastname: King
authors.forename: Sandro
authors.initials: S
authors.lastname: Galea
authors.forename: Samuel R
authors.initials: SR
authors.lastname: Friedman
authors.forename: Brandon D L
authors.initials: BD
authors.lastname: Marshall
mesh_terms: D003198:Computer Simulation; D018562:Disease Transmission, Infectious; D058872:Epidemics; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission*; D006801:Humans; D008297:Male; D009519:New York City / Q000453:epidemiology; D015819:Substance Abuse, Intravenous / Q000150:complications*