title: Per-event probability of hepatitis C infection during sharing of injecting equipment.
abstract: BACKGROUND
  Shared injecting apparatus during drug use is the premier risk factor for hepatitis C virus (HCV) transmission.
  
  
  OBJECTIVE
  To estimate the per-event probability of HCV infection during a sharing event, and the transmission probability of HCV from contaminated injecting apparatus.
  
  
  METHODS
  Estimates were obtained using a maximum likelihood method with estimated IDU and sharing events obtained from behavioural data.
  
  
  METHODS
  Cohort study in multiple correction centres in New South Wales, Australia.
  
  
  METHODS
  Subjects (N = 500) with a lifetime history of injecting drug use (IDU) who were followed up between 2005 and 2012. During follow-up, interviews for risk behaviours were taken and blood sampling (HCV-antibody and RNA testing) was performed.
  
  
  METHODS
  Self-reported frequencies of injecting drugs and sharing events, as well as other risk behaviours and details on the nature of injecting events.
  
  
  RESULTS
  The best estimate of the per-event probability of infection was 0.57% (CI: 0.32-1.05%). A sensitivity analysis on the likely effect of under-reporting of sharing of the injecting apparatus indicated that the per event infection probability may be as low as 0.17% (95% CI: 0.11%-0.25%). The transmission probability was similarly shown to range up to 6%, dependent on the presumed prevalence of the virus in injecting equipment.
  
  
  CONCLUSIONS
  The transmission probability of HCV during a sharing event is small. Hence, strategies to reduce the frequency and sharing of injecting equipment are required, as well as interventions focused on decreasing the per event risk.
authors.affiliation: Inflammation and Infection Research Centre, School of Medical Sciences, The University of New South Wales, Sydney, Australia; Section of Immunology, School of Medicine, Imperial College, London, United Kingdom.
authors.forename: Lies
authors.initials: L
authors.lastname: Boelen
authors.affiliation: Inflammation and Infection Research Centre, School of Medical Sciences, The University of New South Wales, Sydney, Australia.
authors.forename: Suzy
authors.initials: S
authors.lastname: Teutsch
authors.affiliation: The Kirby Institute, The University of New South Wales, Sydney, Australia.
authors.forename: David P
authors.initials: DP
authors.lastname: Wilson
authors.affiliation: National Drug and Alcohol Research Centre, The University of New South Wales, Sydney, Australia.
authors.forename: Kate
authors.initials: K
authors.lastname: Dolan
authors.affiliation: The Kirby Institute, The University of New South Wales, Sydney, Australia.
authors.forename: Greg J
authors.initials: GJ
authors.lastname: Dore
authors.affiliation: Inflammation and Infection Research Centre, School of Medical Sciences, The University of New South Wales, Sydney, Australia.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Lloyd
authors.affiliation: Inflammation and Infection Research Centre, School of Medical Sciences, The University of New South Wales, Sydney, Australia.
authors.forename: Fabio
authors.initials: F
authors.lastname: Luciani
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006526:Hepatitis C / Q000635:transmission*; D006801:Humans; D008297:Male; D016485:Needle Sharing / Q000009:adverse effects*; D011336:Probability; D057566:Self Report; D015819:Substance Abuse, Intravenous / Q000821:virology; D055815:Young Adult