Safety and immunogenicity of 4CMenB and MenACWY-CRM meningococcal vaccines when administered concomitantly in healthy adolescents: A phase 3b, randomized, observer-blind study.

Meningococcal vaccination of adolescents/young adults is recommended in various countries, including the United States (US). This phase 3b, observer-blind study (NCT04318548) evaluated the safety, reactogenicity, and immunogenicity of serogroup B vaccine, 4CMenB, and quadrivalent conjugate vaccine, MenACWY-CRM, when co-administered to healthy individuals aged 16-18 y, as per US Advisory Committee on Immunization Practices recommendations. Adolescents, who had received MenACWY vaccination ≥4 y previously, were randomized (N = 940; 1:1:1) to one of three groups to assess co-administration versus 4CMenB and MenACWY-CRM administered alone. Co-primary objectives were to demonstrate the non-inferiority of antibody responses after concomitant administration to antibody responses after 4CMenB (two doses administered 2 months apart) and MenACWY-CRM (single dose), as measured by human serum bactericidal assay (hSBA). Vaccine safety and reactogenicity were assessed as another primary objective. The co-primary endpoints were met: the lower limit of 2-sided 95% confidence intervals for all between-group ratios of hSBA geometric mean titers was >0.5 for the concomitant administration group versus 4CMenB group and MenACWY-CRM group. hSBA data after two 4CMenB doses and one MenACWY-CRM dose showed comparable between-group geometric mean ratios versus baseline, and percentages of participants with 4-fold rises in titers and titers ≥lower limit of quantitation. The safety profile of 4CMenB co-administered with MenACWY-CRM was comparable with that of 4CMenB administered alone. In conclusion, 4CMenB and MenACWY-CRM co-administration was well tolerated in adolescents aged 16-18 y and immune responses were comparable versus administration of each vaccine alone, which is consistent with a previous study of co-administration in infants.