CAPVAXIVE (Pneumococcal 21-valent Conjugate Vaccine) - (STRIDE-13)

June 18, 2026: Merck (NYSE: MRK) announced the FDA approved an expanded U.S. indication for CAPVAXIVE (pneumococcal 21-valent conjugate vaccine) to include children and adolescents ages 2–17 who have completed a primary pediatric pneumococcal vaccination series and have one or more chronic medical conditions that increase risk for pneumococcal disease. The label includes prevention of invasive pneumococcal disease in at-risk individuals ages 2–17 and 18+, and prevention of pneumococcal pneumonia in adults 18+ (the adult pneumonia indication is under accelerated approval based on opsonophagocytic activity immune responses; continued approval may depend on confirmatory trial clinical benefit).

The pediatric expansion is supported by the Phase 3 STRIDE-13 trial (NCT06177912) in at-risk participants ages 2–17 (n=874) randomized 3:2 to CAPVAXIVE (n=527) vs PPSV23 (n=347). CAPVAXIVE was noninferior to PPSV23 for 12 shared serotypes and produced significantly higher OPA GMTs for 9 serotypes unique to CAPVAXIVE; it also showed immune responses to serotype 15B (cross-reactive to 15C) and was noninferior in a post hoc analysis. Safety was generally comparable; SAEs within 6 months were 5.5% vs 7.2%, with one CAPVAXIVE-related SAE (syncope).