UBC Theses and Dissertations
Hepatitis C virus infection in injection drug users Grebely, Jason Steven
Injection drug users (IDUs) represent the core of the hepatitis C virus (HCV) epidemic, but little is known about the natural history and treatment of HCV in IDUs. This thesis characterizes spontaneous clearance of HCV, investigates HCV re-infection following clearance and evaluates novel models for improving uptake and treatment responses among IDUs. To better understand characteristics associated with HCV clearance in IDUs, data from a community-based cohort study were linked with longitudinal laboratory databases to compare individuals with HCV clearance to those with HCV persistence to evaluate factors associated with clearance of HCV infection. Aboriginal ethnicity and female gender were associated with increased rates of HCV clearance, while HIV co-infection and illicit drug use were associated with increased HCV persistence. To further investigate the impact of illicit drug use on HCV persistence, we compared the rate of re-infection in individuals with HCV clearance to the rate of infection observed in previously uninfected individuals to evaluate whether previous clearance of HCV infection is protective against re-infection. Those with viral clearance were about 4 times less likely to become re-infected than those infected for the first time, suggesting that individuals with HCV clearance have a lower risk of acquiring HCV than individuals who have never been infected, despite ongoing exposure to HCV. Lastly, we sought to evaluate novel models for improving uptake of and response rates to the treatment of HCV among current and former IDUs. First, we demonstrated that within a prospective, multidisciplinary, directly observed therapy program for the treatment of HCV infection of IDUs, overall response rates parallel results from large, randomized controlled trials, despite ongoing illicit drug use during treatment. Second, we demonstrated a high uptake of and response to therapy among IDUs infected with HCV attending a weekly support group. Taken together, these data demonstrate that IDUs can be safely and successfully treated for HCV infection within a multidisciplinary program integrating HCV, addiction and primary care. Given the considerable burden of HCV infection in IDUs, this data contributes significantly to the field by providing a greater understanding of the natural history and treatment of HCV in this setting.
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