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Canadian Journal of Gastroenterology
Volume 21 (2007), Issue 7, Pages 447-451
Original Article

Factors Associated with Spontaneous Clearance of Hepatitis C Virus among Illicit Drug Users

Jason Grebely,1 Jesse D Raffa,2 Calvin Lai,3 Mel Krajden,4 Brian Conway,1 and Mark W Tyndall3,5

1Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
2Department of Statistics, University of British Columbia, Vancouver, British Columbia, Canada
3BC Centre for Excellence in HIV/AIDS, University of British Columbia, Vancouver, British Columbia, Canada
4British Columbia Centre for Disease Control, University of British Columbia, Vancouver, British Columbia, Canada
5Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada

Received 5 October 2006; Accepted 28 November 2006

Copyright © 2007 Hindawi Publishing Corporation. This open-access article is distributed under the terms of the Creative Commons Attribution Non-Commercial License (CC BY-NC) (, which permits reuse, distribution and reproduction of the article, provided that the original work is properly cited and the reuse is restricted to noncommercial purposes.


BACKGROUND: Spontaneous clearance of hepatitis C virus (HCV) occurs in approximately 25% of individuals.

METHODS: To better understand the characteristics associated with clearance, the present study evaluated HCV clearance in a community-based cohort study. The Community Health and Safety Evaluation project recruited 3553 individuals via community organizations and door-to-door canvassing of a random sample of single occupancy hotels in the community to monitor uptake of health services and to estimate the incidence of communicable infections. Cohort data were linked with longitudinal laboratory databases, including HCV antibody and polymerase chain reaction assay results.

RESULTS: Overall, 762 individuals had HCV antibody and RNA testing performed between 1999 and 2005. Spontaneous HCV clearance was observed in 179 individuals (23.5%), while HCV persistence was observed in 583 individuals (76.5%). The ability to develop protective immunity against HCV, as demonstrated by viral clearance, occurred more often in individuals of Aboriginal ethnicity (adjusted OR [AOR] 2.9, 95% CI 2.0 to 4.3; P<0.001) and female individuals (AOR 1.6, 95% CI 1.1 to 2.4; P=0.01). The rate of spontaneous HCV clearance was reduced in individuals using any type of illicit drugs (AOR 0.54, 95% CI 0.29 to 1.00; P=0.05) and those with HIV coinfection (AOR 0.58, 95% CI 0.38 to 0.88; P=0.01). Of 218 HIV-infected subjects, 48 of 51 (94%) in whom the order of HCV and HIV infection was established were infected with HCV a median of 2.4 years (range 0.2 to 10 years) before becoming infected with HIV.

CONCLUSIONS: Aboriginal ethnicity and female sex were associated with increased rates of HCV clearance, while HIV coinfection and illicit drug use were associated with increased HCV persistence.