Enhanced surveillance of hepatitis B in Canada, 1999–2004: Implication for immunization policy

Abstract

We aimed to describe the current HBV incidence and patterns of transmission in Canada, as well as discussing implications for the control of HBV through immunization. We analyzed acute hepatitis B cases reported to the Enhanced Hepatitis Strain Surveillance System during the period 1999–2004 from 7 health sentinel Regions in Canada. The incidence of acute hepatitis B per 100,000 population significantly declined, from 2.05 in 1999 to 0.93 in 2004 (p < 0.001; RR, 0.85; 95% CI, 0.80–0.90). Rates of disease were averaged to be 2.8 times (95% CI, 2.28–3.46) higher among males than among females. The greatest decline occurred among individuals 30–39 years old (75.0%), followed by those 10–19 years old (72.3%) and 20–29 years old (63.8%) (P < 0.001 for each age group). During 1999–2004, the most commonly reported risk factor for infection was high-risk sexual activity (22%) followed by IDU (17%) and MSM activity (13%). The decline of the incidence observed can be attributable to predonation blood screening, promotion of safer sex, and implementation of vaccination. Endemic transmission may be further reduced by improving immunization coverage among certain high risk groups (IDU, MSM, high-risk sexual activity). This continued strategy will dramatically limit the number of acute infections.