Response to primary and booster vaccination with 10-valent pneumococcal nontypeable haemophilus influenzae protein D conjugate vaccine in Korean infants

Background: This randomized single-blind study in Korea evaluated noninferiority of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) versus the 7-valent pneumococcal conjugate vaccine (7vCRM) when both were coadministered with H. influenzae type b (Hib) conjugate vaccine, as opposed to coadministration with diphtheria-tetanus- acellular pertussis-based combination vaccines in previous studies. Methods: Infants received 3 primary doses at 2, 4, and 6 months and a booster dose at 12 to 18 months of PHiD-CV (N = 374) or 7vCRM (N = 129), both coadministered with Hib vaccine. Immune responses were measured 1 month postdose 3 and postbooster using 22F-inhibition enzyme-linked immunosorbent assay and functional opsonophagocytic activity assay. Results: PHiD-CV-induced antibody responses against each of the vaccine pneumococcal serotypes and protein D. Noninferiority to 7vCRM was demonstrated for all 10 PHiD-CV serotypes in terms of percentages of subjects reaching an antibody concentration 0.2 μg/mL after primary vaccination. Postprimary and postbooster, percentages of subjects with antibody concentration 0.2 μg/mL or opsonophagocytic activity titer 8 were generally consistent between groups for each pneumococcal serotype common to both vaccines. The safety and reactogenicity profiles of PHiD-CV and 7vCRM were generally comparable after both primary and booster vaccination. Conclusions: In this Korean study, 3-dose PHiD-CV priming followed by a booster dose was immunogenic for all 10 vaccine pneumococcal serotypes and protein D. Noninferiority to 7vCRM in terms of enzyme-linked immunosorbent assay threshold responses postpriming was demonstrated. The safety and reactogenicity profiles of both vaccines when coadministered with Hib vaccine were generally comparable.