Safety, immunogenicity, and immune memory of a novel meningococcal (groups A, C, Y, and W-135) polysaccharide diphtheria toxoid conjugate vaccine (MCV-4) in healthy adolescents

Objective: A meningococcal (groups A, C, Y, and W-135) polysaccharide diphtheria toxoid conjugate vaccine (MCV-4; Menactra; Sanofi Pasteur Inc, Swift-water, Pa) was developed to improve the profile of currently licensed products. The objective of this study was to compare the tolerability, immunogenicity, and immune memory of MCV-4 with those of a quadrivalent polysaccharide vaccine (PSV-4; Menomune A/C/Y/W-135; Sanofi Pasteur Inc). Design, Setting, Participants: A randomized, double-blind trial was performed at 11 clinical centers in the United States. The vaccine MCV-4 or PSV-4 was administered to 881 healthy 11- to 18-year-olds. Sera were collected prevaccination and 28 days postvaccination. Three-year follow-up and booster vaccination with MCV-4 were performed in a participant subset from each group and a control group. Main Outcome Measures: Proportion of participants with a 4-fold or greater increase in serum bactericidal antibody against each serogroup 28 days after initial vaccination, geometric mean serum bactericidal antibody titers, and safety assessments. Results: Both vaccines were well tolerated; most reactions were mild. More MCV-4 recipients reported solicited local reactions (68.9%) than PSV-4 recipients (30.2%). Both MCV-4 and PSV-4 were highly immunogenic; similar proportions of participants had 4-fold or greater increases in serum bactericidal antibody (range, 80.1%-96.7%) to the 4 serogroups. Three-year follow-up showed persistence of serum bactericidal antibody and booster responses to MCV-4 consistent with immune memory in participants previously vaccinated with MCV-4, but not in those who had previously received PSV-4. Conclusions: The vaccine MCV-4 was well tolerated and highly immunogenic. Persistence of bactericidal activity with MCV-4, but not PSV-4, was evident 3 years after the initial immunization. Booster response was demonstrated after a second vaccination with MCV-4.