Immune response to different types of hepatitis B vaccine booster doses 2-32 years after the primary immunization schedule and its influencing factors.

Objective: To assess the immune effect of different types of hepatitis B vaccine (HepB) booster doses 2-32 years after primary immunization, explore the influencing factors, and offer guidance regarding the necessity and timing of boosters.

Methods: In total, 1163 participants who were born from 1986 to 2015, received the HepB full-course primary vaccination, were hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (anti-HBc) negative, and had hepatitis B surface antibody (anti-HBs) <10 mIU/mL were enrolled. Individuals were randomly divided into two groups and received a booster dose of HepB. Venous blood samples were collected 30 days later and tested for anti-HBs.

Results: In total, 595 and 568 individuals received a single dose of HepB (CHO) and HepB (SC), respectively. Venous blood samples were obtained from 1079 vaccinees (CHO: 554, SC: 525). The seroconversion rates were 93.68% (519/554) and 86.67% (455/525) (p < 0.05), with geometric mean concentrations (GMCs) of 426.58 mIU/ml and 223.8 mIU/ml, respectively. This result indicated that BMI, smoking status, vaccine types of booster and prebooster anti-HBs concentration significantly influenced anti-HBs levels. Only BMI, prebooster anti-HBs concentrations and booster types were different between the anti-HBs positive and negative groups.

Conclusions: Participants boostered with HepB (CHO) had a relatively higher seroconversion rate than those boostered with HepB (SC). The high seroconversion rates in the two groups suggested that the subjects remained protected despite low circulating antibodies, so there is currently no urgent need for booster immunization. Factors including BMI ≥ 25 and prebooster anti-HBs concentration <2.5 mIU/mL, which contributed to lower responses to a booster dose, might indicate a greater risk of breakthrough infection.