Persistence of bactericidal antibodies following booster vaccination with 4CMenB at 12, 18 or 24Â months and immunogenicity of a fifth dose administered at 4Â years of age-a phase 3 extension to a randomised controlled trial

Waning of protective antibodies occurred 12-36 months after toddler booster regardless of age at boost. This was least marked against target strains 5/99 and M10713. A robust memory response occurred after a booster dose given at 4 years of age.