Impact of neonatal hepatitis B vaccination programme on age-specific prevalence of hepatitis B infection in teenage mothers in Hong Kong

Abstract

SUMMARYWe examined the impact of the neonatal hepatitis B immunization programme, first provided to all neonates born to mothers screened positive for hepatitis B surface antigen (HBsAg) in late 1983, on the age-specific prevalence of HBsAg carriage in teenage mothers managed in 1998–2008. HBsAg carriage was found in 2·5%, 2·7%, 8·8% and 8·0% of mothers aged ⩽16, 17, 18, and 19 years, respectively (P = 0·004), which was also correlated with advancing age (P = 0·011). While neither difference nor correlation with age was found in mothers born before 1984, the prevalence of 1·2%, 1·5%, 7·1% and 8·3%, respectively, was significantly different among (P = 0·008) and correlated with (P = 0·002) age in mothers born 1984 onwards. Regression analysis indicated there was a significantly higher incidence of HBsAg carriage from age 17 onwards (adjusted odds ratio 2·55, 95% confidence interval 1·07–6·10,P = 0·035), suggesting that the protective effect of the vaccine declined in late adolescence.