Safety and immunogenicity of a 3-dose schedule of a quadrivalent meningococcal tetanus toxoid conjugate vaccine administered concomitantly with routine pediatric vaccines to infants and toddlers: A descriptive randomized study.

MenACYW-TT (MenQuadfi®), a quadrivalent meningococcal conjugate vaccine, is approved for use in individuals aged ≥12 months or ≥6 weeks depending on the country. This study reported the immunogenicity and safety of MenACYW-TT in individuals aged <12 months. This phase III, open-label, randomized, active-controlled study described the immunogenicity and safety of a 3-dose (2 + 1) immunization schedule of MenACYW-TT in Mexico and the Russian Federation or a 4-dose (3 + 1) immunization schedule of MCV4-CRM in Mexico, when co-administered with routine pediatric vaccines to healthy infants and toddlers aged 2 to 12 months (NCT03630705). The immunogenicity of meningococcal serogroups was assessed by serum bactericidal antibody assays using human complement. The safety data were collected for up to 30 d following vaccination. MenACYW-TT demonstrated high seroprotection rates in Mexico and in the Russian Federation after the last vaccination (booster) at 12 months of age. The proportion of participants achieving seroresponse to all 4 meningococcal serogroups after receiving 2 doses of MenACYW-TT in the infant series was comparable to the proportion of those receiving 3 doses of MCV4-CRM in Mexico. There was no clinically relevant effect on the immunogenicity and safety profile of the routine pediatric vaccines when administered concomitantly with MenACYW-TT at the same visit. No safety concern was observed during this study. MenACYW-TT demonstrated a safety profile generally comparable with that of MCV4-CRM when administered concomitantly with routine pediatric vaccines. The MenACYW-TT conjugate vaccine in a 2 + 1 schedule demonstrated an acceptable immunogenicity and safety profile.