Hepatitis A in south-eastern Sydney 1997-1999: continuing concerns for gay men and an outbreak among illicit drug users.

The incidence of hepatitis A virus (HAV) in south-eastern Sydney is one of the highest in Australia with large outbreaks previously associated with male-to-male sexual contact. We report HAV notification trends over the period 1 June 1997 to 31 May 1999 for this location. In the first twelve-month period, 233 cases were notified (crude rate 30.5/100,000 per year) with a peak incidence of 110/100,000 in males aged 20-39 years. Over 60% of male cases reported male-to-male sexual contact. The notification rate (crude rate 15.5/100,000) and proportion of males (61%) was considerably lower in the following twelve month period with 118 cases notified. Less than a third of males reported male-to-male sexual contact. An outbreak (n = 45) of HAV among illicit drug users and their contacts was detected in December 1998. The transmission of HAV remains endemic in south-eastern Sydney. Vaccination among high-risk groups remains an important preventive strategy.