title: Hepatitis C virus reinfection in injection drug users.
abstract: Spontaneous clearance of hepatitis C (HCV) may provide protection against reinfection. In a large community-based cohort study of 3,553 inner-city residents (mainly injection drug users), we identified HCV-infected individuals in whom virological clearance had occurred and compared the rate of reinfection in this group with that observed in previously uninfected members of the same cohort. We identified 926 HCV-uninfected and 658 HCV-infected viremic subjects at baseline, with 152 of 658 (23.1%) spontaneously clearing viremia over a median follow-up of 5.2 years (IQR, 2.8-7.4). At baseline, individuals with HCV clearance were more likely to be HIV coinfected (P < .001) and to be engaged in frequent illicit drug use (P = .004) and injection drug use (P < .001). The occurrence of HCV infection was lower in individuals with previous infection (14/152, 9.2%) compared with that in those without previous infection (172/926, 18.6%), with incidence rates of 1.8 (95% CI, 0.9-3.0 cases/100 person-years) and 8.1 (95% CI, 6.9-9.4 cases/100 person-years) cases/100 person-years, respectively, after accounting for follow-up. In a logistic regression analysis, with previous HCV infection assessed as a covariate with other potential confounding variables (age, sex, ethnicity, HIV infection, housing status, and illicit and injection drug use), individuals with previous HCV infection and viral clearance were 4 times less likely to develop infection than those infected for the first time (adjusted odds ratio, 0.23; 95% CI, 0.10-0.51, P < .001). In conclusion, individuals with clearance of HCV infection may have a lower risk of acquiring HCV than individuals who have never been infected, despite ongoing exposure to HCV.
authors.affiliation: Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada. jgrebely@interchange.ubc.ca
authors.forename: Jason
authors.initials: J
authors.lastname: Grebely
authors.forename: Brian
authors.initials: B
authors.lastname: Conway
authors.forename: Jesse D
authors.initials: JD
authors.lastname: Raffa
authors.forename: Calvin
authors.initials: C
authors.lastname: Lai
authors.forename: Mel
authors.initials: M
authors.lastname: Krajden
authors.forename: Mark W
authors.initials: MW
authors.lastname: Tyndall
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000453:epidemiology; D016174:Hepacivirus / Q000276:immunology / Q000302:isolation & purification*; D006526:Hepatitis C / Q000150:complications / Q000453:epidemiology / Q000821:virology*; D018937:Hepatitis C Antibodies / Q000097:blood*; D006801:Humans; D007113:Immunity, Innate; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D012367:RNA, Viral / Q000032:analysis; D012008:Recurrence; D012075:Remission, Spontaneous; D015819:Substance Abuse, Intravenous / Q000097:blood / Q000821:virology*; D014766:Viremia / Q000276:immunology
chemical_list: D018937:Hepatitis C Antibodies; D012367:RNA, Viral