Oral Presentation 25th International Pathogenic Neisseria Conference 2026

A single adolescent dose of 4CMenB effectively boosts immune responses up to 19 years after priming in infancy: Results from a phase 3b, open-label, multicenter study (141317)

Giancarlo Icardi 1 , Federico Martinón-Torres 2 , Ignacio Salamanca de la Cueva 3 4 , Santtu Heinonen 5 , Simon Drysdale 6 7 , Eva Galiza 8 , Eleonora Cei 9 , Luca Moraschini 9 , Mauro Trapani 9 , Danielle Morelle 10 , Maria Lattanzi 9 , Laureano Mestra 9 , Pavitra Keshavan 9
  1. Department of Health Sciences, University of Genoa, Genoa, Italy
  2. Hospital Clínico Universitario de Santiago, Santiago De Compostela, Spain
  3. Unidad de Investigación, Grupo IHP, Sevilla, Spain
  4. Universidad de Málaga, Málaga, Spain
  5. Finnish Vaccine Research (FVR), Tampere, Finland
  6. Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK
  7. The NIHR Oxford Biomedical Research Centre, Oxford, UK
  8. Vaccine Institute & Centre for Neonatal and Paediatric Infection, City St George's, University of London, UK
  9. GSK, Sienna, Italy
  10. GSK, Rixensart, Belgium

BACKGROUND

Waning immunity after meningococcal serogroup B (MenB) vaccination in infancy potentially leaves adolescents unprotected during the second peak of MenB disease. This study assessed immune responses to a booster dose of four-component MenB vaccine, 4CMenB (Bexsero, GSK), in individuals aged 10–20 years who were vaccinated as infants, compared to the first dose in individuals never previously vaccinated against MenB (NCT06995430).

METHODS

The study included two groups (3:1 ratio): participants primed with 4CMenB (2+1 or 3+1 infant schedule) received one 4CMenB dose (primed group; N=234); participants not previously MenB-vaccinated received two 4CMenB doses one month apart (naïve group; N=78). The primary objective was to demonstrate superiority of the immune response to one 4CMenB booster dose in the primed group compared to the first dose in the naïve group against each of four MenB indicator strains, based on the between-group ratio of human serum bactericidal assay (hSBA) geometric mean titers (GMTs) one month post-vaccination. Safety and reactogenicity were evaluated as a secondary objective.

RESULTS

The primary endpoint was met, demonstrating superiority of the booster dose. Post-vaccination between-group GMT ratios (primed:naïve) were 3.89 (95% confidence interval [CI]: 2.778–5.461) for fHbp, 15.55 (95% CI: 10.723–22.546) for NadA, 1.35 (95% CI: 1.004–1.820) for NHBA, and 1.77 (95% CI: 1.247–2.499) for PorA. Lower limits of 95% CIs were all >1. Immunogenicity results for subgroups of participants aged 10–15 years and 16–20 years were consistent with the overall results. Responses were higher in the primed group despite higher-than-expected post-dose 1 responses in the naïve group. Percentages of participants with hSBA titers ≥4 were 87.9% for fHbp, 99.1% for NadA, 85.7% for NHBA, and 70.7% for PorA in the primed group and, respectively, 64.1%, 87.2%, 56.6%, and 41.6% in the naïve group. 4CMenB was well tolerated, with no safety concerns identified.

CONCLUSIONS

A 4CMenB vaccination course in infants can prime the immune system and induce a memory response that can be boosted by a single dose in adolescence up to 19 years later. Booster dose safety and reactogenicity were consistent with the established 4CMenB safety profile.

Funding: GSK.