RT Journal Article SR Electronic T1 Persistence of immunity after vaccination with a capsular group B meningococcal vaccine in 3 different toddler schedules JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E1276 OP E1285 DO 10.1503/cmaj.161288 VO 189 IS 41 A1 Manish Sadarangani A1 Tim Sell A1 Mildred A. Iro A1 Matthew D. Snape A1 Merryn Voysey A1 Adam Finn A1 Paul T. Heath A1 Gianni Bona A1 Susanna Esposito A1 Javier Diez-Domingo A1 Roman Prymula A1 Adefowope Odueyungbo A1 Daniela Toneatto A1 Andrew J. Pollard A1 , YR 2017 UL http://www.cmaj.ca/content/189/41/E1276.abstract AB BACKGROUND: One schedule for the capsular group B meningococcal vaccine 4CMenB is 2 doses that are administered 2 months apart for children aged 12–23 months, with a booster dose 12–24 months later. Our objective was to provide data on persistence of human serum bactericidal antibody (hSBA) titres in children up to 4 years of age after initial doses at 12–24 months, and immunogenicity of a booster dose at 48 months of age compared with vaccine-naive children.METHODS: Children previously immunized, as part of a randomized controlled trial, with 2 doses of 4CMenB vaccine at 12–24 months of age received a booster at 4 years of age. Vaccine-naive age-matched toddlers received 2 doses of 4CMenB. Human serum bactericidal antibody titres against reference strains H44/76, 5/99, NZ98/254 and M10713 were evaluated before and after innoculation with 4CMenB vaccine in 4-year-old children.RESULTS: Of 332 children in the study, 123 had previously received 4CMenB and 209 were vaccine-naive controls. Before the booster, the proportions of participants (previously vaccinated groups compared with controls) with hSBA titres of 1:5 or more were as follows: 9%–11% v. 1% (H44/76), 84%–100% v. 4% (5/99), 0%–18% v. 0% (NZ98/254) and 59%–60% v. 60% (M10713). After 1 dose of 4CMenB in previously immunized children, the proportions of participants achieving hSBA titres of 1:5 or more were 100% (H44/76 and 5/99), 70%–100% (NZ98/254) and 90%–100% (M10713).INTERPRETATION: We found that waning of hSBA titres by 4 years of age occurred after 2 doses of 4CMenB vaccine administered at 12–24 months, and doses at 12–24 months have a priming effect on the immune system. A booster may be necessary to maintain hSBA titres of 1:5 or more among those children with increased disease risk. Trial registration: ClinicalTrials.gov, no. NCT01717638