Immediate and longer term immunogenicity of a single dose of the combined haemophilus influenzae type B-Neisseria meningitidis serogroup C-tetanus toxoid conjugate vaccine in primed toddlers 12 to 18 months of age.

Hib-primed but MenC-naive toddlers (N = 433) were randomized to receive 1 dose of Hib-MenC-TT or separate Hib-TT and MenC-CRM197 vaccines. One month later, noninferiority was demonstrated for serum bactericidal anti-MenC antibodies (rSBA) and Hib antipolyribosylribitol phosphate (PRP) antibodies; >99% in both groups had rSBA titer ≥ 8 or anti-PRP concentration ≥ 0.15 μg/mL. After 12 months, rSBA titer ≥ 8 persisted in 86.7% and 76.4%, and anti-PRP concentration ≥ 0.15 μg/mL persisted in 98.8% and 100% of children, respectively.