FIG. 1.

The correlation (Spearman's correlation coefficient; P < 0.001 for all serotypes and time points) and a linear regression model for the IgG anti-6B, -19F, and -23F antibody concentrations (EIA, μg/ml) and OPA titers after three (7 months) and four (13 months) doses of vaccine. The children were immunized with 7-valent pneumococcal conjugate vaccine (PncCRM or PncOMPC) at 2, 4, and 6 months of age and either with the homologous vaccine or 23-valent polysaccharide vaccine (PncPS) at 12 months of age. All children boosted with PncPS had previously received three doses of PncOMPC.