Seroprevalence of hepatitis B and C virus infections: Results from the 2007 to 2009 and 2009 to 2011 Canadian Health Measures Survey.

BACKGROUND Chronic hepatitis B (HBV) and C (HCV) virus infections can lead to liver failure, liver cancer, and death. In Canada, prevalence studies of HBV and HCV have been limited to regional and special populations. DATA AND METHODS Data are from cycles 1 (2007 to 2009) and 2 (2009 to 2011) of the Canadian Health Measures. Socio-demographic, health and lifestyle information was obtained via a household questionnaire; blood samples collected at mobile examination centres were used to identify present and resolved HBV infections, vaccine-induced HBV immunity, and HCV infections. RESULTS The seroprevalence of present HBV infection among the population aged 14 to 79 was 0.4%, representing an estimated 111,800 individuals. Another 4.2% had evidence of a previous HBV infection. Nearly 30% had vaccine-induced HBV immunity. The seroprevalence of HCV infection was 0.5%, representing an estimated 138,600. More than half of people with laboratory-confirmed HBV and 70% with laboratory-confirmed HCV were unaware of their infections. INTERPRETATION This is the first Canadian study to report laboratory-confirmed seroprevalence of HBV and HCV infections based on a nationally representative household sample. Substantial percentages of younger Canadians have vaccine-induced HBV immunity.