Immune Persistence, Immunogenicity and Safety of a Quadrivalent Meningococcal Conjugate Vaccine (MenACYW-TT) Administered as a Booster Dose in Adolescents and Adults Vaccinated Against Meningococcal Disease 3 - 6 Years Earlier

Background: Booster doses of meningococcal conjugate vaccines may induce long-term protection against invasive meningococcal disease. MenACYW-TT (MenQuadfi®) is a quadrivalent meningococcal conjugate vaccine, licensed for use in ages 2 years and older in the USA. The vaccine is also licensed in ages 12 months and older in the EU and certain other countries.

Methods: A phase IIIb study was conducted to evaluate the persistence of immune response in adolescents and adults primed 3-6 years earlier (at ages 10-17 years) with either MenACYW-TT or MCV4-CRM (Menveo®). The study also evaluated the safety and immunogenicity of MenACYW-TT when administered as a booster dose with or without concomitant administration with MenB vaccine (Bexsero® or Trumenba®). Serum bactericidal assays with human complement (hSBA) and baby rabbit complement (rSBA) were used to measure antibodies against vaccine serogroups at baseline (Day 0 [D0]), D06 (in a subset) and 30 days post-booster vaccination (D30). Safety data were collected up to 6 months post-booster vaccination.

Results: At D0, the hSBA Geometric Mean Titers (GMTs) were higher in participants primed 3-6 years earlier with MenACYW-TT vs MCV4-CRM for serogroups C, Y and W, and were comparable for serogroup A. At D0, all hSBA GMTs were higher than those observed pre-priming dose, suggesting persistence of immunity. Sufficiency of hSBA seroresponse (lower limit of 1 sided 97.5% confidence interval >75% for all four serogroups) was demonstrated following administration of MenACYW-TT booster dose regardless of the priming vaccine administered 3-6 years earlier. Vaccine seroresponse in a subset of participants at D06 ranged from 77.8% (95%CI 62.9%; 88.8%) for serogroup A to 97.8% (88.5%; 99.9%) for serogroup W suggesting a quick onset of immune response post-booster. Post-vaccination (D30) hSBA GMTs were comparable for serogroups A, Y and W regardless of the nature of the priming vaccine and were higher for serogroup C in subjects primed with MenACYW-TT vaccine. Immune response to all four serogroups (A, C, W and Y) were comparable when MenACYW-TT vaccine was administered alone or co-administered with either of the two MenB vaccines. The MenACYW-TT booster dose was well-tolerated and had similar safety profiles regardless of the priming vaccine. The safety profiles were comparable regardless of the MenB vaccine co-administered with MenACYW-TT vaccine.

Conclusion: MenACYW-TT used as priming vaccine demonstrated persistence of immune response 3-6 years later. Booster vaccination with MenACYW-TT was safe and elicits robust bactericidal antibody responses in adolescents and adults primed with MenACYW-TT or MCV4-CRM. No evidence of interference in the immune response to the MenACYW-TT vaccine was observed on co-administration with MenB vaccines. In addition, co-administration of a MenACYW-TT booster with MenB vaccine did not reveal any safety concerns.