ABSTRACT
BACKGROUND: Invasive meningococcal disease has its highest incidence in infants. Co-administration of serogroup B (4CMenB) and quadrivalent conjugate (MenACWY-CRM) vaccines could protect against 5 clinically-relevant meningococcal serogroups. METHODS: This phase 3b, open, multicenter study (NCT02106390), conducted in Mexico and Argentina, enrolled and randomized (1:1:1) 750 healthy infants to receive either 4CMenB co-administered with MenACWY-CRM (4CMenB/MenACWY group), 4CMenB (4CMenB group), or MenACWY-CRM alone (MenACWY group) at ages 3, 5, 7 and 13â¯months. Non-inferiority of immune responses of co-administration to single administration of vaccines was assessed at 1â¯month post-booster dose (primary objective). Immunogenicity was evaluated pre- and 1â¯month post-primary and booster vaccinations using human serum bactericidal assay (hSBA). Safety was assessed. RESULTS: At 1â¯month post-booster vaccination, between-group hSBA geometric mean titer (GMT) ratios ranged from 0.89 to 1.03 for serogroup B strains (group 4CMenB/MenACWY over 4CMenB), and from 1.05 to 2.48 for ACWY serogroups (group 4CMenB/MenACWY over MenACWY). The lower limit of the 2-sided 95% confidence intervals for all GMT ratios was >0.5; the primary objective was demonstrated. Across all groups and serogroup B strains, 68-100% and 87-100% of children had hSBA titers ≥5 at 1â¯month post-primary and booster vaccination, respectively. For serogroups ACWY, ≥96% (post-primary vaccination) and ≥98% (post-booster vaccination) of children in all groups had hSBA titers ≥4. Post-booster vaccination, GMTs increased ≥5.99-fold from pre-booster values for each strain/serogroup. Solicited adverse events (AEs) were more frequent in groups 4CMenB/MenACWY and 4CMenB than in MenACWY; incidence of all other AEs was similar between groups. Serious AEs were reported for 6, 13, and 11 participants in groups 4CMenB/MenACWY, 4CMenB, and MenACWY, respectively; 1 (group 4CMenB) was considered vaccine-related. CONCLUSION: Immune responses elicited by co-administration of 4CMenB and MenACWY-CRM was non-inferior to single immunization. Co-administration of vaccines was immunogenic and well tolerated in infants. ClinicalTrials.gov: NCT02106390.