Seroprevalence of Hepatitis B Viral Markers Among Freshmen — 20 Years After Mass Hepatitis B Vaccination Program in Taiwan

Abstract

The nationwide hepatitis B vaccination program in Taiwan was well known for its efficacy in reducing the carrier rate of hepatitis B and the morbidity and mortality of hepatitis B-related diseases among children. The aim of this study was to investigate the seroprevalence of hepatitis B 20 years after this program was implemented. A total of 7592 freshmen from one university in Northern Taiwan participated in this study during their school entry health exam in September 2003 and September 2004. Basic data including gender, birthday, family history and vaccination history of hepatitis B by self-reported questionnaire were collected. Hepatitis B serum markers, including hepatitis B surface antigen, antibody against hepatitis B surface antigen, and antibody against hepatitis B core antigen were all checked. The differences in the seroprevalence of hepatitis B between two groups of subjects born before July 1984 and after July 1984 were examined. Multiple logistic analyses were performed for identifying the odds ratio (OR) of family history and other variables for each hepatitis B serum marker. Subjects born after July 1984 were found to have a lower rate of hepatitis B surface antigen of 2.2% (95% confidence interval [CI], 1.8-2.6%) vs. 7.4% (95% CI, 5.9-8.9%), and core antibody against hepatitis B of 6.7% (95% CI, 6.0-7.3%) vs. 23.5% (95% CI, 21.1-25.9%), but a higher rate of surface antibody against hepatitis B of 74.3% (95% CI, 73.2-75.4%) vs. 69.1% (95% CI, 66.5-71.7%) compared with those born before July 1984 (all p < 0.001). Subjects with a family history of hepatitis B had higher risk of being infected by hepatitis B (OR, 4.07; 95% CI, 3.18-5.12) and becoming carriers (OR, 7.26; 95% CI, 5.05-10.44) after adjustment for sex, age, birth year, and self-reported hepatitis B vaccination history. The seroprevalence of hepatitis B surface antigen continued to decline 20 years after neonatal hepatitis B vaccination program. It is strongly recommended that those who have a family history of hepatitis B should receive early check-up of hepatitis B status after complete vaccination or closely follow up their hepatitis B status after neonatal hepatitis B vaccination.