Figure 4. Pneumococcal opsonophagocytic activity (OPA) geometric mean titers (GMTs) and geometric mean fold rises (GMFRs) in participants aged ≥60 years for the 13 matched ( A ) and 7 additional ( B ) serotypes before and 1 month after vaccination. Substantial increases in OPA GMTs from baseline to 1 month after vaccination were observed in both groups. Assay results below the lower limit of quantitation (LLOQ) were set to 0.5 × LLOQ. The numbers of subjects with valid and determinate assay results for the specified serotypes varied by serotype and were 1360–1425 for 20-valent pneumococcal conjugate vaccine (PCV20) and 1294–1418 for 13-valent pneumococcal conjugate vaccine (PCV13) for the 13 matched serotypes and 973–1353 for PCV20 and 993–1293 for 23-valent pneumococcal polysaccharide vaccine (PPSV23) for the 7 additional serotypes.