This report summarizes the results of work collated from various sources on the prevalence of viral hepatitis in the past three decades in Hong Kong.

The annual incidence of hepatitis A has been declining in the past ten years. The prevalence of hepatitis A was also falling in the last two decades, especially in those aged below 40. This provided the fertile soil for outbreaks of hepatitis A which are now occurring every few years. Declining immunity in the population was also one of the reasons why the total incidence had been increasing in successive outbreaks.

The hepatitis B carrier rate of the general population in Hong Kong was estimated to be about 10% in 1978. Nevertheless, recent studies from different sources revealed a declining trend over time. The HBsAg prevalence rate is found to vary with age, being especially low in children under the age of 10. The prevalence rate in adults also differs from one community group to another. This is compounded by differences in sampling method used in the studies reported. The HBsAg carrier rate is above 10% in older age groups and also people with HIV/AIDS. In antenatal women, it is approximately 10%. In police officers, it is only 6.2%.

Screening of healthy blood donors indicates that some 0.2-0.3% are infected with hepatitis C, comparable to studies from abroad. The prevalent genotypes are 1b and 6. The prevalence is much higher, at over 50%, in intravenous drug users and hemophiliacs.

The data on hepatitis E infection is insufficient for any conclusion to be made.