Reduced schedules of 4CMenB vaccine in infants and catch-up series in children: Immunogenicity and safety results from a randomised open-label phase 3b trial.

Background: This study evaluated the immunogenicity and safety of a licensed meningococcal serogroup B vaccine (4CMenB) administered alone according to reduced schedules in infants or catch-up series in children.

Methods: In this open-label, multicentre, phase 3b study (NCT01339923), infants randomised 1:1:1 received 4CMenB: 2+1 doses at 3½-5-11months or 6-8-11months of age, 3+1 doses at ages 2½-3½-5-11months. Children aged 2-10years received 2 catch-up doses administered 2months apart. Immune responses were measured by hSBA assays against 4 strains specific for vaccine components fHbp, NadA, PorA and NHBA. Sufficiency of immune responses was defined in groups with 2+1 doses schedules as a lower limit ≥70% for the 97.5% confidence interval of the percentage of infants with hSBA titres ≥4, 1month post-dose 2 for fHbp, NadA, PorA. Adverse events were collected for 7days post-vaccination; serious adverse events (SAEs) throughout the study.

Results: 754 infants and 404 children were enrolled. Post-primary vaccination, 98-100% of infants across all groups developed hSBA titres ≥4 for fHbp, NadA, PorA, and 48-77% for NHBA. Sufficiency of immune responses in infants receiving 2+1 schedules was demonstrated for fHbp, NadA, PorA after 2 doses of 4CMenB, as pre-specified criteria were met. Following receipt of 2 catch-up doses, 95-99% of children developed hSBA titres ≥4 for 4CMenB components. Similar safety profiles were observed across groups. A total of 45 SAEs were reported, 3 of which were related to vaccination.

Conclusion: Reduced infant schedules and catch-up series in children were immunogenic and safe, having the potential to widen 4CMenB vaccine coverage.

Funding: GlaxoSmithKline Biologicals SA.