title: Hepatitis C reinfection after sustained virological response.
abstract: OBJECTIVE
  On-going risk behaviour can lead to hepatitis C virus (HCV) reinfection following successful treatment. We aimed to assess the incidence of persistent HCV reinfection in a population of people who inject drugs (PWID) who had achieved sustained virological response (SVR) seven years earlier.
  
  
  METHODS
  In 2004-2006 we conducted a multicentre treatment trial comprising HCV genotype 2 or 3 patients in Sweden, Norway and Denmark (NORTH-C). Six months of abstinence from injecting drug use (IDU) was required before treatment. All Norwegian patients who had obtained SVR (n=161) were eligible for participation in this long-term follow-up study assessing virological and behavioural characteristics.
  
  
  RESULTS
  Follow-up data were available in 138 of 161 (86%) individuals. Persistent reinfection was identified in 10 of 94 (11%) individuals with a history of IDU prior to treatment (incidence rate 1.7/100 person-years (PY); 95% CI 0.8-3.1) and in 10 of 37 (27%) individuals who had relapsed to IDU after treatment (incidence rate 4.9/100 PY; 95% CI 2.3-8.9). Although relapse to IDU perfectly predicted reinfection, no baseline factor was associated with reinfection. Relapse to IDU was associated with age <30 years (vs. ⩾40 years) at treatment (adjusted odds ratio [aOR] 7.03; 95% CI 1.78-27.8) and low education level (aOR 3.64; 95% CI 1.44-9.18).
  
  
  CONCLUSIONS
  Over time, persistent HCV reinfection was common among individuals who had relapsed to IDU after treatment. Reinfection should be systematically addressed and prevented when providing HCV care for PWID.
authors.affiliation: Department of Infectious Diseases, Akershus University Hospital, Lørenskog, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway. Electronic address: havardmi@medisin.uio.no.
authors.forename: Håvard
authors.initials: H
authors.lastname: Midgard
authors.affiliation: Department of Transplantation Medicine, Oslo University Hospital, Oslo, Norway.
authors.forename: Benedikte
authors.initials: B
authors.lastname: Bjøro
authors.affiliation: Department of Infectious Diseases, Oslo University Hospital, Oslo, Norway.
authors.forename: Arild
authors.initials: A
authors.lastname: Mæland
authors.affiliation: Department of Gastroenterology, Oslo University Hospital, Oslo, Norway.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Konopski
authors.affiliation: Section of Gastroenterology, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Hege
authors.initials: H
authors.lastname: Kileng
authors.affiliation: Centre of Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Infectious Diseases, St. Olav's Hospital, Trondheim, Norway.
authors.forename: Jan K
authors.initials: JK
authors.lastname: Damås
authors.affiliation: Section of Gastroenterology, Telemark Hospital Trust, Skien, Norway.
authors.forename: Jørn
authors.initials: J
authors.lastname: Paulsen
authors.affiliation: Section of Infectious Diseases, Vestre Viken Hospital Trust, Drammen, Norway.
authors.forename: Lars
authors.initials: L
authors.lastname: Heggelund
authors.affiliation: Department of Medicine, Østfold Hospital Trust, Grålum, Norway.
authors.forename: Per K
authors.initials: PK
authors.lastname: Sandvei
authors.affiliation: Department of Medicine, Østfold Hospital Trust, Grålum, Norway.
authors.forename: Jetmund O
authors.initials: JO
authors.lastname: Ringstad
authors.affiliation: Department of Medicine, Stavanger University Hospital, Stavanger, Norway.
authors.forename: Lars N
authors.initials: LN
authors.lastname: Karlsen
authors.affiliation: Department of Virology, The Norwegian Institute for Public Health, Oslo, Norway.
authors.forename: Kathrine
authors.initials: K
authors.lastname: Stene-Johansen
authors.affiliation: Department of Virology, The Norwegian Institute for Public Health, Oslo, Norway.
authors.forename: John H-O
authors.initials: JH
authors.lastname: Pettersson
authors.affiliation: Department of Virology, The Norwegian Institute for Public Health, Oslo, Norway.
authors.forename: Dagny H
authors.initials: DH
authors.lastname: Dorenberg
authors.affiliation: Department of Infectious Diseases, Akershus University Hospital, Lørenskog, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Olav
authors.initials: O
authors.lastname: Dalgard
mesh_terms: D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use*; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D016174:Hepacivirus / Q000235:genetics*; D019698:Hepatitis C, Chronic / Q000188:drug therapy* / Q000453:epidemiology / Q000821:virology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D016017:Odds Ratio; D012367:RNA, Viral / Q000235:genetics*; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D000072230:Sustained Virologic Response; D013548:Sweden / Q000453:epidemiology; D019562:Viral Load / Q000187:drug effects*
chemical_list: D000998:Antiviral Agents; D012367:RNA, Viral
keywords: HCV; Incidence; Injecting drug use; PWID; Reinfection; Risk behaviour