18-year follow-up study of a prospective randomized trial of hepatitis B vaccinations without booster doses in children

The long-term immunogenicity and efficacy of hepatitis B (HBV) vaccination remain to the defined. We aimed to examine the long-term immunogenicity and efficacy of HBV vaccination with 3 different regimens over 18 years of follow-up. Methods: A total of 318 Chinese subjects receiving 3 different regimens of HBV vaccination (2-dose recombinant vs. 3-dose recombinant vs. 3-dose plasma-derived vaccines) without receiving a booster dose were recruited. The HBV serologic markers, including hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), were determined at yearly follow-up. After 18 years, 88 subjects were still being followed up. Results: Compared with subjects receiving the 2-dose regimen, subjects receiving the 3-dose regimens had a significantly higher geometric mean titer of anti-HBs and a higher proportion had anti-HBs titers>10 m IU/mL during the 18 years of follow-up. There were no differences in these 2 parameters between subjects receiving the 3-dose plasma-derived vaccines. A total of 88 anamnestic responses were documented in 70 subjects (8 with initial anti-HBs titers <100m IU/Ml at 12 months and 7 with anti-HBs titers <10 m IU/mL before the anamnestic responses). No subject became positive for HBsAg. Three subjects had benign breakthrough HBV infection without leading to chronicity indicated by isolated anti-HBV infection without leading to chronicity indicated by isolated anti-HBc positivity. Conclusions: There was less long-term immunogenicity associated with the 2-dose regimen when compared with the 3-dose regimens of HBV vaccination. Because of the highly effective anamnestic responses, a booster dose was not necessary at least up to 18 years after the primary vaccination.