The current seroepidemiology of hepatitis A in Hong Kong was examined by testing stored sera from 702 healthy subjects, collected between 1987-1989, for antibody to hepatitis A virus (anti-HAV). The overall prevalence of anti-HAV antibody was 45.6%. There were significant increases in prevalence of anti-HAV antibody with every 10-year increase in age up to age 40. The prevalence of anti-HAV antibody was 24% for subjects below age 30 and 89.2% for those above age 30 (P < 0.0001). Socioeconomic factors did not appear to have any influence on the prevalence of anti-HAV antibody. In comparison with another study conducted in Hong Kong 10 years ago, the prevalence of anti-HAV antibody in the current study was significantly lower in every age group from 0 to 30 years. In summary, it was shown that HAV infection is no longer highly endemic in Hong Kong. In view of the changing epidemiology, postexposure prophylaxis will be necessary for young adults and children, and hepatitis A vaccine may be indicated for high risk groups when it is generally available.
