Enhanced surveillance of acute hepatitis B in south-eastern Sydney.

Hepatitis B is a notifiable condition in all Australian states and territories. Medical practitioners and health facilities are required to report episodes of acute disease, while laboratories must notify on positive serological results. In New South Wales laboratories are required to report only the presence of hepatitis B surface antigen (HBsAg). Without clinical information, laboratory reporting of HBsAg fails to distinguish between acute infection and chronic carriage. Since practitioner under reporting is well recognised, surveillance data are likely to underestimate the true incidence of acute clinical infection. Two retrospective reviews of an enhanced surveillance system to improve the identification of acute hepatitis B in south-eastern Sydney are presented. Over a 6-month period, the enhanced surveillance system increased the identification of acute cases by at least threefold. Over a 5-year period, medical practitioners or hospitals reported only 25 per cent of acute disease, the remainder being initially notified by laboratories. Approximately half of the laboratory notifications contained only HBsAg results. The availability of clinical notes, liver enzyme or IgM to core antigen results assisted the public health unit in the identification of possible acute disease. This system of enhanced surveillance has proven to be sustainable, with minimal resources required. We suggest that sentinel enhanced surveillance systems in a sample of New South Wales public health units would be an effective and efficient method to improve the surveillance of acute hepatitis B, and that laboratories be required to report IgM to core antigen, if available, when notifying a positive HBsAg result.