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A cross-sectional analysis of acute hepatitis B virus reported to the Vancouver Coastal Health Authority from 2000 to 2003.

BACKGROUND
Acute hepatitis B virus (HBV) transmission remains a significant public health problem despite effective vaccination and prophylaxis strategies. Vancouver, British Columbia, has a large ethnic community from endemic areas, which may further impact on the epidemiology of acute HBV. A cross-sectional study of factors associated with acute HBV cases reported to the Vancouver Coastal Health Authority (Vancouver, British Columbia) from 2000 to 2003 is reported.


METHODS
New seropositive cases of hepatitis B surface antigen were reported to the Vancouver Coastal Health Authority Office of Communicable Disease Control. Patients meeting both clinical and laboratory criteria for acute HBV were interviewed by telephone for demographic and risk behaviour information. Risk behaviours within the last six months before disease onset were ranked on efficiency of transmission in a mutually exclusive risk category.


RESULTS
There were 78 patients of identified acute HBV in Vancouver from 2000 to 2003. The overall incidence rate was 3.38 per 100,000 person years. Outside of Canada, Asia was the most common place of birth (29.5%). The three most frequently identified risk factors were men who have sex with men (21.9%), heterosexual activity with two or more partners (14.0%) and intravenous drug use (14.0%). Sexual contact with an HBV carrier was identified in 9.4% of patients.


CONCLUSIONS
Sexual transmission is a major mode in the spread of HBV in Vancouver. Existing public education, surveillance and vaccination strategies for HBV need to be strengthened to address those engaging in risky behaviours.