Long-term Immune Responses to Pneumococcal Conjugate Vaccines in Children Previously Vaccinated With 7-valent Pneumococcal Conjugate Vaccine

Abstract

Seven-valent pneumococcal conjugate vaccine (PCV7) has reduced incidence of vaccine-serotype pneumococcal diseases. Using a single dose of 13-valent pneumoccal conjugate vaccine (PCV13), we evaluated late immune responses 10 years after vaccination with PCV7 in infancy, compared with a PCV7-naïve cohort. In this open-label study, we administered 1 dose of PCV13 to children aged 11-14 years who had previously received PCV7 (PCV7/PCV13) or meningococcal group C conjugate vaccine (MnCC/PCV13) during infancy. We evaluated serotype-specific immunoglobulin G concentrations and opsonophagocytic activity prevaccination and 1 week and 1 month postvaccination. We recorded local reactions and systemic events for 4 days postvaccination and adverse events for 6 months. Seventy-four subjects received PCV13 (PCV7/PCV13, n = 38; MnCC/PCV13, n = 36). Prevaccination with PCV13, >62.9% of subjects had immunoglobulin G concentrations ≥0.35 µg/mL for all serotypes except serotype 4 (28-29%); proportions increased at 1 month postvaccination to 100% for all serotypes except serotypes 3 (PCV7/PCV13, 94.7%; MnCC/PCV13, 97.0%) and 14 (MnCC/PCV13, 97.1%). Immunoglobulin G and opsonophagocytic activity concentrations for the 7 common and 6 additional serotypes were similar in both groups prevaccination and increased in both groups from prevaccination to 1 week and 1 month postvaccination. Local reactions and fever were mild or moderate; no serious adverse events were reported. Late immune responses after a single dose of PCV13 were similar in children aged 11-14 years regardless of previous vaccination with PCV7 or MnCC. PCV13 was immunogenic, safe and well tolerated.