Immunogenicity and Safety of a Booster Dose of the 10-valent Pneumococcal Haemophilus Influenzae Protein D Conjugate Vaccine Coadministered With the Tetravalent Meningococcal Serogroups A, C, W-135 and Y Tetanus Toxoid Conjugate Vaccine in Toddlers: A Randomized Trial

Background: This open, randomized clinical trial (NCT00758264) evaluated the coadministration of a booster dose of the 10-valent pneumococcal conjugate vaccine (PHiD-CV) and a single dose of the tetravalent meningococcal conjugate vaccine (MenACWY-TT) in Taiwanese and Mexican toddlers. Methods: Healthy toddlers aged 12-23 months (N = 363) were randomized (2:1:1) to receive either both vaccines at first visit, MenACWY-TT at first visit and 1 month later PHiD-CV, or PHiD-CV at first visit and 1 month later MenACWY-TT. Immune responses were measured 1 month after MenACWY-TT vaccination by meningococcal serum bactericidal activity (rSBA) assay and 1 month after PHiD-CV vaccination by pneumococcal 22F-inhibition enzyme-linked immunosorbent assay and functional opsonophagocytic activity assay. Solicited and unsolicited symptoms were recorded for days 4 and 31 postvaccination, respectively. Serious adverse events were recorded throughout the study. Results: The prespecified criteria for noninferiority of coadministration versus individual administrations were met for all meningococcal serogroups (in terms of percentages of toddlers with rSBA titer >= 8) and all vaccine pneumococcal serotypes (in terms of antibody geometric mean concentration ratios), except pneumococcal serotype 18C. For each meningococcal serogroup, >= 97.5% of toddlers across the 3 groups had rSBA titers >= 128 at 1 month after MenACWY-TT vaccination. For each pneumococcal serotype, at 1 month after PHiD-CV vaccination, >= 96.0% and >= 92.9% of toddlers across the 3 groups had antibody concentrations >= 0.2 mu g/mL and opsonophagocytic activity titers >= 8, respectively. The safety profiles of both vaccines when coadministered were clinically acceptable. Conclusions: This study supports the coadministration of PHiD-CV and MenACWY-TT in toddlers.