Low cord blood type 14 pneumococcal IgG1 but not IgG2 antibody predicts early infant otitis media.

Type-specific IgG1 and IgG2 antibodies to Streptococcus pneumoniae capsular polysaccharides 14 and 19F were measured in cord blood samples from 425 neonates, to determine which antibody subclass was most strongly associated with otitis media (OM) during the first 6 months of life (early OM). Early OM was significantly associated with type 14 IgG1 antibody in the lowest antibody quartile (P=.055) but not with type 19F IgG1 antibody or with either IgG2 antibody. IgG1 and IgG2 antibodies were significantly intercorrelated for type 14 (r=.52, P<.001) and type 19F (r=.38, P<.001). Multivariate analysis revealed that having type 14 IgG1 antibody in the lowest quartile, child care attendance, and sibling and maternal OM history were independent risk factors for early OM. Although type-specific pneumococcal IgG2 antibody concentrations were significantly higher than IgG1 concentrations, IgG2 antibodies apparently are not protective against OM during early infancy.