Long-term efficacy and anamnestic response of hepatitis B vaccine derived from Chinese hamster ovary cell after 18-20 years.

To evaluate the long-term efficacy and anamnestic response of Chinese hamster ovary (CHO) cell-derived hepatitis B vaccine (CHO-HepB) after 18-20 years, a cross-sectional survey was conducted in seven communities in Zhengding County at the end of 2017. The birth cohort 1997-1999 vaccinated primarily with three doses of CHO-HepB were enrolled in the survey. The HBV serological markers were quantified using the Chemiluminescence method. The infection status of HBsAg-positive participants was determined by comparing their results with the previous data. For those with an anti-HBs antibody negative, the anamnestic response was evaluated by measuring anti-HBs antibody concentrations following a dose of HepB administration. A total of 1352 participants were enrolled, with the prevalence of HBsAg, anti-HBs, and anti-HBc being 0.4 %, 74.5 %, and 1.3 %, respectively. There was no significant difference in the HBV markers (HBsAg, anti-HBs and anti-HBc) between birth-year groups (P > 0.05). The geometric mean concentration (GMC) of anti-HBs antibodies among 1007 positive participants was 191 mIU/ml. No new infections or carriers were identified in the survey. Combined with the three previous surveys of the same birth cohort, the positive rates of HBsAg, anti-HBs, and anti-HBc remained largely unchanged over two decades following CHO-HepB vaccination. Of 248 participants who received a booster vaccination, 231 (93.1 %) showed an anti-HBs antibody positive with a GMC of 369 mIU/mL. Moreover, the positive rate and GMC of anti-HBs were higher in the CHO-HepB booster group compared to the Saccharomyces cerevisiae-HepB booster group. The long-term efficacy of the CHO-HepB remains stable for 18-20 years after primary vaccination, and a higher seroconversion rate of anti-HBs is observed following a booster vaccination of CHO-HepB. Given the absence of new infections or carriers over the past two decades, it appears unnecessary to administer a booster vaccination of HepB.