A Territorywide Prevalence Study on Blood-Borne and Enteric Viral Hepatitis in Hong Kong

Background: Viral hepatitis epidemiological data are important for the World Health Organization plan of eliminating viral hepatitis. We aimed to document the prevalence of viral hepatitis A to E in Hong Kong.

Methods: This community-based study was open to all Hong Kong Chinese citizens aged ≥18 years. Baseline data and risk factors were collected. Hepatitis A-E serology was measured, including hepatitis B e antigen, antibodies to hepatitis B e antigen, antibodies to hepatitis D, hepatitis B virus (HBV) DNA for hepatitis B surface antigen (HBsAg)-positive participants, and antibodies to hepatitis B surface antigen and antibodies to hepatitis B core antigen (anti-HBc) in HBsAg-negative participants. Hepatitis C virus (HCV) RNA and genotypes were determined in anti-HCV-positive participants.

Results: A total of 10 256 participants were recruited from February 2015 to July 2016. Overall HBsAg seroprevalence was 7.8% (95% confidence interval [CI], 7.3%-8.3%), which was reduced significantly with HBV vaccination (odds ratio, 0.15 [95% CI, .11-.21]). Among HBsAg-negative participants, anti-HBc seroprevalence increased from 5.4% (<26 years) to 60.1% (>65 years). No hepatitis D virus (HDV) cases were detected. Anti-HCV positivity was 0.5% (95% CI, .3%-.6%). Prevalence of antibodies to hepatitis A virus (anti-HAV) and hepatitis E virus (anti-HEV) was 65.2% (95% CI, 64.2%-66.1%) and 33.3% (95% CI, 32.4%-34.2%), respectively, and were influenced by age, family income, and being born in mainland China.

Conclusions: HBV seroprevalence remained high despite universal vaccination. High anti-HBc seroprevalence underlines the potential issue of HBV reactivation during profound immunosuppression. HCV and HDV remained uncommon. Anti-HAV seroprevalence had decreased whereas anti-HEV seroprevalence had risen.