Minimization of hepatitis B infection by a 25-year universal vaccination program

Abstract

Background & aims: Hepatitis B virus (HBV) infection was hyperendemic in Taiwan before the implementation of the universal infant hepatitis B immunization program, which was launched in 1984. Five previous seroepidemiologic surveys were conducted at 0, 5, 10, 15, and 20 years after the launch of the vaccination program.

Methods: We enrolled 3332 subjects younger than 30 years of age, with approximately 100 of them in each age cohort. Subjects were recruited voluntarily from schools and other institutions in Taipei, as in previous surveys. HBV seromarkers included hepatitis B surface antigen (HBsAg) and antibodies to HBsAg (anti-HBs) and hepatitis B core antigen (anti-HBc). HBV DNA levels were measured in anti-HBc positive/HBsAg negative subjects (anti-HBc only).

Results: The HBsAg, anti-HBs, and anti-HBc seropositive rates were very different between subjects born after the program in 2009 and the baseline group in 1984 (0.9% vs. 10%, 55.9% vs. 24.5%, and 7.0% vs. 28%, respectively). In this 6th survey, we showed that HBsAg prevalence further decreased in the vaccinated cohorts. A positive maternal HBsAg status was found in 86% of vaccine failures. Serum HBV DNA was detected in 4.2% (6/142) of anti-HBc positive/HBsAg negative subjects, with a low level of HBV DNA. All of these six subjects' HBV were genotype C.

Conclusions: The universal infant HBV immunization program in Taiwan has completed its 25-year follow-up and its efficacy in young adults is clear. The continued decrease in HBsAg prevalence suggests that the elimination of HBV infection is becoming a reality.