(A) Relationship between serum opsonic activity and level of anticapsular antibody against pneumococcus type 6B. Immunization was at 2, 4, and 6 months of age for infants with SCD (●) and control infants (○). Immunization was at 12 months of age for infants with SCD (■) and control infants (□). rho, Spearman's correlation coefficient. (B) Relationship between serum opsonic activity and level of anticapsular antibody against pneumococcus type 14. Immunization was at 2, 4, and 6 months for infants with SCD (●) and control infants. Immunization was at 12 months of age for infants with SCD (■) and control infants (□). rho, Spearman's correlation coefficient.