A phase III randomized study: Immunogenicity and safety of a quadrivalent meningococcal conjugate vaccine in healthy adults, adolescents, and children in India and healthy adolescents and children in South Africa

Background: MenACYW-TT is a quadrivalent meningococcal conjugate vaccine approved for individuals aged ≥6 weeks. This Phase III study evaluated the immunogenicity and safety of a single dose of MenACYW-TT versus MenACYW-DT and MenPS-ACWY in healthy adults, adolescents, and children in India and in healthy adolescents and children in South Africa. Methods: In total, 1,328 participants were randomized by age into three cohorts (Cohort Ia: adults aged 18–55 years, India [N=198]; Cohort Ib: adults aged ≥56 years, India [N=200]; Cohort II: children and adolescents aged 2–17 years, India [N=465] and South Africa [N=465]). The immunogenicity of vaccines was assessed with a serum bactericidal assay using human complement (hSBA). The primary objective was to demonstrate the non-inferiority of immunogenicity of a single dose of MenACYW-TT versus MenACYW-DT in children and adolescents aged 2–17 years in terms of hSBA titers in India and South Africa. Results: The primary objective was met. The non-inferiority of MenACYW-TT versus MenACYW-DT was demonstrated on post-vaccination Day 30 in participants aged 2–17 years. The lower limit of the 95% confidence interval for the difference in the percentages of the participants achieving seroprotection (hSBA titers ≥1:8) against all four serogroups was greater than −10%. MenACYW-TT demonstrated robust immunogenicity in adults aged 18–55 years and ≥56 years in India. The rates of solicited injection site and systemic reactions were comparable between the participants who received MenACYW-TT versus licensed comparator vaccines. No vaccine-related serious adverse events, study discontinuations, or deaths were reported. Conclusions: A single dose of MenACYW-TT induced non-inferior immune responses and a comparable safety profile versus MenACYW-DT in children and adolescents aged 2–17 years. MenACYW-TT was well tolerated and immunogenic in adults, adolescents, and children in India and in adolescents and children in South Africa.