Association of Serotype-Specific Antibody Concentrations and Functional Antibody Titers with Subsequent Pneumococcal Carriage in Toddlers Immunized with a 9-Valent Pneumococcal Conjugate Vaccine

Association of pneumococcal nasopharyngeal carriage with the concentration and opsonophagocytic activity (OPA) of serum serotype-specific antibodies was determined for toddlers 1 month after immunization with a 9-valent pneumococcal conjugate vaccine. Higher anti-serotype 14 and anti-serotype 19F IgG and anti-serotype 14 IgM correlated with a lowered probability of pneumococcal acquisition. Postvaccination OPA did not correlate with pneumococcal carriage.