Antibody persistence and booster response in adolescents and young adults 4 and 7.5 years after immunization with 4CMenB vaccine.

•4–7.5 years post-2-dose 4CMenB primary series, 9–84% of subjects had hSBA titers ≥4 for ≥1 vaccine antigen.•Antibody levels were higher in primed versus vaccine-naïve individuals of similar age.•Post-booster, 93–100% of primed subjects had hSBA titers ≥4 against all antigens.•Kinetics showed an early robust immune response at 7 days post-booster/second dose.•The study raised no new safety concerns and overall, the vaccine was well-tolerated.