Immunogenicity and safety of 13-valent pneumococcal conjugate vaccine given to korean children receiving routine pediatric vaccines.

BACKGROUND

The immunogenicity and safety of 13-valent and 7-valent pneumococcal conjugate vaccines (PCV13 and PCV7) were compared when administered with routine vaccines in Korea.

METHODS

Healthy infants (n = 180) were randomly assigned (1:1) to receive PCV13 or PCV7 at 2, 4, 6 (infant series) and 12 months (toddler dose). Immune responses 1 month after the infant series and toddler dose were measured by enzyme-linked immunosorbent assay and opsonophagocytic activity (OPA) assay. IgG antibody geometric mean concentrations and OPA functional antibody geometric mean titers were calculated. Safety was assessed.

RESULTS

After the infant series, for the 7 common serotypes, proportions of responders with IgG concentrations ≥0.35 µg/mL were comparable (≥97.6%) between groups; IgG geometric mean concentrations and OPA geometric mean titers were generally similar, but tended to be lower in the PCV13 group for some serotypes. For the 6 serotypes unique to PCV13, IgG geometric mean concentrations and OPA geometric mean titers were notably higher in the PCV13 group. Importantly, although PCV7 elicited IgG antibodies to PCV13 serotypes 5 and 19A, OPA responses were minimal, whereas serotype 6A elicited both IgG and OPA responses. These observations are consistent with at least some protection by PCV7 against 6A-mediated invasive pneumococcal disease, but no cross-protection for serotypes 5 and 19A. The toddler dose elicited higher IgG and OPA responses than postinfant series responses for most serotypes; however, for serotypes 3 and 14 only OPA responses were increased posttoddler dose. Vaccine safety profiles were similar.

CONCLUSIONS

PCV13 is safe and immunogenic in Korean children. PCV13 should provide broader protection than PCV7.