Immunogenicity and Safety of a Quadrivalent Meningococcal Tetanus Toxoid­-Conjugate Vaccine (MenACYW­-TT) Administered Concomitantly with Pneumococcal Conjugate Vaccine in Healthy Toddlers in the Russian Federation: a Phase III Randomized Study

Relevance. Invasive meningococcal disease (IMD) has high morbidity and mortality, with infants and young children among those at greatest risk.Materials & Methods. A phase III, open-­label, randomized study in toddlers aged 12–23 months evaluated the immunogenicity and safety of MenACYW­TT, a tetanus toxoid conjugated vaccine against meningococcal serogroups A, C, W, and Y, when coadministered with paediatric vaccines (measles, mumps and rubella [MMR]; varicella [V] in South Korea and Thailand; 6­in­1 combination vaccine against diphtheria, tetanus, pertussis, polio, hepatitis B and Haemophilus influenzae type b [DTaP­IPVHepB­Hib] in Mexico and pneumococcal conjugate vaccine [PCV13]) in the Russian Federation (NCT03205371). This manuscript reports the outcome of the part of the study conducted in the Russian Federation using PCV13 as the co­administered vaccine. Immunogenicity to each meningococcal serogroup was assessed by serum bactericidal antibody assay using human complement (hSBA) and, for a subset of subjects, baby rabbit complement (rSBA). Vaccine safety profiles were described up to 30 days postvaccination.Results. A total of 1,183 participants were enrolled in the study, out of which 400 were from the Russian Federation. The proportion with seroprotection (hSBA ≥1:8) to each meningococcal serogroup at Day 30 was comparable between the MenACYW­-TT and MenACYW-­TT + PCV13 groups (≥91% and ≥84%, respectively). The safety profiles of MenACYW­-TT and PCV13, when given alone or concomitantly, were generally comparable.Conclusion. Coadministration of MenACYW­-TT with pneumococcal conjugate vaccine in toddlers had no clinically relevant effect on the immunogenicity and safety of any of the vaccines.