Effect of Increased CRM197Carrier Protein Dose on Meningococcal C Bactericidal Antibody Response

Abstract

ABSTRACTNew multivalent CRM197-based conjugate vaccines are available for childhood immunization. Clinical studies were reviewed to assess meningococcal group C (MenC) antibody responses following MenC-CRM197coadministration with CRM197-based pneumococcal orHaemophilus influenzaetype b conjugate vaccines. Infants receiving a total CRM197carrier protein dose of ∼50 μg and concomitant diphtheria-tetanus-acellular pertussis (DTaP)-containing vaccine tended to have lower MenC geometric mean antibody titers and continued to have low titers after the toddler dose. Nevertheless, at least 95% of children in the reported studies achieved a MenC serum bactericidal antibody (SBA) titer of ≥1:8 after the last infant or toddler dose. SBA was measured using an assay with a baby rabbit or human complement source. Additional studies are needed to assess long-term antibody persistence and MenC CRM197conjugate vaccine immunogenicity using alternative dosing schedules.