Cutland CL, et al. - This investigation was pursued to assess the immunogenicity and safety of 1 and 2 doses of quadrivalent meningococcal serogroup A, C, W and Y tetanus toxoid-conjugate vaccine (MenACWY-TT) given alone or co-administered with 13-valent pneumococcal conjugate vaccine (PCV13) in toddlers. Single dose of MenACWY-TT, when administered at 12–14 months of age, demonstrated immunogenicity. Increased human complement serum bactericidal antibody assay responses against meningococcal serogroups W and meningococcal serogroups Y were reported as a result of administering the second dose in toddlers. MenACWY-TT and PCV13 can be co-administered without impairing the immunogenicity or safety profile of either vaccine.