Prevalence and Incidence of Hepatitis B Infection among Hepatitis C Virus-Infected Subjects in 6 Health Regions, Canada, 1998–2006

Purpose To determine the prevalence and incidence of hepatitis B virus (HBV) infection among hepatitis C virus (HCV)-infected subjects and compare sociodemographic and risk characteristics between HBV/HCV co-infected and HCV-monoinfected patients. Methods Data were collected through the Enhanced Hepatitis Strain Surveillance System from 6 sentinel regions in Canada. Univariate and multivariate logistic regression analysis were undertaken to investigate predictors of co-infection. Results During the period 1998-2006, the cumulative incidence of acute HBV among HCV-infected subjects was 490 per 100,000 (67 cases). Factors independently associated with acute HBV infection were injection drug use (odds ratio [OR] = 3.7, 95% confidence interval [CI]: 1.5, 9.1). An 8-year prevalence of HBV infection was 2.8% (95% CI: 2.5, 3.1). Independent association with baseline co-infection included being male (OR=2.0, 95% CI: 1.6, 2.6), being non-Canadian-born persons (OR=2.6, 95% CI: 1.9, 3.4), and being older age (OR=1.3, 95% CI: 1.0, 1.6). Of subjects with known information on HBV vaccination, ≥1 dose of HBV vaccine was 27%. HBV rates were much higher in the HCV-infected people than in the general population, and HBV vaccination coverage levels were low. Conclusions There were a sizable number of HCV-infected patients co-infected with HBV, particularly male and non-Canadian-born patients. Since combined chronic hepatitis B and C is associated with more severe liver disease and an increased risk of hepatocellular carcinoma, the need for outreach HBV vaccination programs is emphasized not only in the target high-risk population but also in HCV-infected patients.