 The significance of vaccination against Hepatitis B during infancy is recognized worldwide, that the need for booster or a vaccination after a period of time following primary vaccination remains controversial. Recent studies suggest that age-specific increased HBSAG prevalence in subjects born after mass vaccination may be due to imperfect coverage at the beginning of its introduction and carryover of infection from early life. Booster response has been observed in individuals vaccinated 30 years ago, but confirmed breakthrough HBV infection with severe consequences is rare. A longitudinal study following the same cohort of participants may provide more direct evidence to determine whether a vaccination of Hepatitis B vaccine is necessary. This article was authored by Hongzhou and Yehua Ju.