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Incidence, risk factors, and prevention of hepatitis C reinfection: a population-based cohort study
Nazrul Islam1, Mel Krajden2, Jean Shoveller3
1School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada; British Columbia Centre for Disease Control, Vancouver, BC, Canada.
Insights
Hepatitis C virus (HCV) reinfection is common, especially in people who inject drugs (PWID). Opioid substitution therapy and mental health support significantly reduce reinfection risk in PWID, highlighting the need for continued harm-reduction services.
Area of Science:
- Hepatology
- Infectious Diseases
- Public Health
Background:
- Hepatitis C virus (HCV) infection can recur even after initial clearance.
- Understanding reinfection risk factors is crucial for effective prevention strategies.
Purpose of the Study:
- To identify factors associated with HCV reinfection risk.
- To examine the impact of opioid substitution therapy and mental health counselling on HCV reinfection among people who inject drugs (PWID).
Main Methods:
- A population-based cohort study in British Columbia, Canada, analyzed data from 1990-2013.
- HCV reinfection was defined by positive HCV PCR tests after spontaneous clearance or sustained virological response (SVR).
- Multivariable Cox proportional hazards models were used to assess risk factors and treatment associations.
Main Results:
- The overall HCV reinfection rate was 1.27 per 100 person-years.
- Higher reinfection risks were observed in individuals with spontaneous clearance, HIV co-infection, and among PWID.
- Opioid substitution therapy (adjusted HR 0.73) and mental health counselling (adjusted HR 0.71) were associated with lower reinfection risk in PWID.
Conclusions:
- HCV reinfection incidence is elevated in specific populations, including those with spontaneous clearance, HIV co-infection, and PWID.
- Integrating opioid substitution therapy and mental health counselling into HCV treatment can mitigate reinfection risk for PWID.
- Findings support policies for post-clearance follow-up and harm-reduction services for PWID to minimize HCV transmission.
Background:
People remain at risk of reinfection with hepatitis C virus (HCV), even after clearance of the primary infection. We identified factors associated with HCV reinfection risk in a large population-based cohort study in British Columbia, Canada, and examined the association of opioid substitution therapy and mental health counselling with reinfection.
Methods:
We obtained data from the British Columbia Hepatitis Testers Cohort, which includes all individuals tested for HCV or HIV at the British Columbia Centre for Disease Control Public Health Laboratory during 1990-2013 (when data were available). We defined cases of HCV reinfection as individuals with a positive HCV PCR test after either spontaneous clearance (two consecutive negative HCV PCR tests spaced ≥28 days apart without treatment) or a sustained virological response (SVR; two consecutive negative HCV PCR tests spaced ≥28 days apart 12 weeks after completing interferon-based treatment). We calculated incidence rates of HCV reinfection (per 100 person-years of follow-up) and corresponding 95% CIs assuming a Poisson distribution, and used a multivariable Cox proportional hazards model to examine reinfection risk factors (age, birth cohort, sex, year of HCV diagnosis, HCV clearance type, HIV co-infection, number of mental health counselling visits, levels of material and social deprivation, and alcohol and injection drug use), and the association of opioid substitution therapy and mental health counselling with HCV reinfection among people who inject drugs (PWID).
Findings:
5915 individuals with HCV were included in this study after clearance (3690 after spontaneous clearance and 2225 after SVR). 452 (8%) patients developed reinfection; 402 (11%) after spontaneous clearance and 50 (2%) who had achieved SVR. Individuals were followed up for a median of 5·4 years (IQR 2·9-8·7), and the median time to reinfection was 3·0 years (1·5-5·4). The overall incidence rate of reinfection was 1·27 (95% CI 1·15-1·39) per 100 person-years of follow-up over a total of 35 672 person-years, with significantly higher rates in the spontaneous clearance group (1·59, 1·44-1·76) than in the SVR group (0·48, 0·36-0·63). With the adjusted Cox proportional hazards model, we noted higher reinfection risks in the spontaneous clearance group (adjusted hazard ratio [HR] 2·71, 95% CI 2·00-3·68), individuals co-infected with HIV (2·25, 1·78-2·85), and PWID (1·53, 1·21-1·92) than with other reinfection risk factors. Among the 1604 PWID with a current history of injection drug use, opioid substitution therapy was significantly associated with a lower risk of reinfection (adjusted HR 0·73, 95% CI 0·54-0·98), as was engagement with mental health counselling services (0·71, 0·54-0·92).
Interpretation:
The incidence of HCV reinfection was higher among HIV co-infected individuals, those who spontaneously cleared HCV infection, and PWID. HCV treatment complemented with opioid substitution therapy and mental health counselling could reduce HCV reinfection risk among PWID. These findings support policies of post-clearance follow-up of PWID, and provision of harm-reduction services to minimise HCV reinfection and transmission.
Funding:
The British Columbia Centre for Disease Control and the Canadian Institutes of Health Research.