Terence T Lao1, Daljit S Sahota2, Paul K S Chan3. 1. Departments of Obstetrics & Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin NT, Hong Kong, China. Electronic address: lao-tt@cuhk.edu.hk. 2. Departments of Obstetrics & Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin NT, Hong Kong, China. 3. Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China.
Abstract
OBJECTIVES: To evaluate the impact of three decades of hepatitis B vaccination in infancy on antenatal prevalence of hepatitis B surface antigen (HBsAg) carriage in 93,134 Hong-Kong born gravidae managed in 1997-2015. METHODS: Annual prevalence of HBsAg carriage on routine antenatal screening was examined with respect to maternal year of birth in three periods i.e. pre-1983 (before availability of vaccination), 1983-1988 (vaccination of infants born to HBsAg-carriers), and after 1988 (universal vaccination). RESULTS: Overall HBsAg carriage was 8.3% (7737/93,134), decreasing from 10.5% in 1997 to 6.5% in 2015 (p < 0.001), and from 8.8%, 7.0% to 3.1%, respectively, for the three period-of-birth cohorts (p < 0.001). Annual prevalence decreased from 9.9% in 1997 to 7.5% in 2015 (p < 0.001) in the pre-1983 cohort, but showed neither difference nor trend in the other two cohorts. However, the annual prevalence showed significantly falling trends from the pre-1983 to the post-1988 cohorts for the years 2007-2008 and 2010-2015. CONCLUSIONS: A progressive decline in overall annual prevalence of antenatal HBsAg carriage was found, with a consistently significant decline among the three cohorts for the years 2007-2008 and 2010-2015, providing evidence that universal hepatitis B vaccination in infancy has reduced significantly antenatal prevalence of HBsAg carriage in Hong Kong.
OBJECTIVES: To evaluate the impact of three decades of hepatitis B vaccination in infancy on antenatal prevalence of hepatitis B surface antigen (HBsAg) carriage in 93,134 Hong-Kong born gravidae managed in 1997-2015. METHODS: Annual prevalence of HBsAg carriage on routine antenatal screening was examined with respect to maternal year of birth in three periods i.e. pre-1983 (before availability of vaccination), 1983-1988 (vaccination of infants born to HBsAg-carriers), and after 1988 (universal vaccination). RESULTS: Overall HBsAg carriage was 8.3% (7737/93,134), decreasing from 10.5% in 1997 to 6.5% in 2015 (p < 0.001), and from 8.8%, 7.0% to 3.1%, respectively, for the three period-of-birth cohorts (p < 0.001). Annual prevalence decreased from 9.9% in 1997 to 7.5% in 2015 (p < 0.001) in the pre-1983 cohort, but showed neither difference nor trend in the other two cohorts. However, the annual prevalence showed significantly falling trends from the pre-1983 to the post-1988 cohorts for the years 2007-2008 and 2010-2015. CONCLUSIONS: A progressive decline in overall annual prevalence of antenatal HBsAg carriage was found, with a consistently significant decline among the three cohorts for the years 2007-2008 and 2010-2015, providing evidence that universal hepatitis B vaccination in infancy has reduced significantly antenatal prevalence of HBsAg carriage in Hong Kong.