Identification of chronic hepatitis B and hepatitis C co-infection in British Columbia from 1991 to 2007.

OBJECTIVES To determine the chronic HBV/HCV co-infection identification rate in British Columbia, and examine the demographic characteristics, the order of virus identification, and trends of co-infection over time. METHODS All newly identified cases of chronic HBV/HCV co-infection between 1991 and October 2007 were extracted from the BC integrated Public Health Information System. Differences according to sex and order of hepatitis identification were evaluated using chi-square, t-tests, and ANOVA. RESULTS Of 1,815 HBV/HCV co-infected residents, 71.6% were male and the mean age at co-infection diagnosis was 40.5 years (95% CI, 40.0-41.0; range 3-85 years). Among all persons identified with HCV infection, 3.1% were identified as co-infected with HBV and 5.2% of all chronic HBV-infected were diagnosed with HCV. Annual co-infection identification rates peaked at 5.3 per 100,000 in 1996. Females were significantly younger when they were first diagnosed with a hepatitis virus (p=0.0005) at 35.2 years (95% CI, 34.0-36.5; range 3-79 years) than males at 37.9 years (95% CI, 37.0-39.7; range 4-85 years). The majority of co-infections consisted of concurrent diagnoses until 2003; since then, the number of co-infected cases identified with HBV first, HCV first and concurrent virus identification is similar. DISCUSSION HBV/HCV co-infection identification rates have declined since the late 1990s, but appropriate testing and identification for both viruses are important. Some co-infection cases may be prevented through HBV vaccination and harm reduction activities for those with or at risk for HCV.