Response to LetteR

Pneumococcal polysaccharide vaccines have demonstrated effectiveness in prevention of invasive pneumococcal disease (IPD).1 However, their effectiveness against non-invasive pneu-mococcal pneumonia or all-cause community-acquired pneu-monia (CAP) has not been established; two recently published meta-analyses concluded that prevention of pneumococcal pneu-monia could not be demonstrated for pneumococcal polysaccha-ride vaccines.2,3 By contrast, conjugated pneumococcal vaccines have proven effective against pneumococcal pneumonia and all-cause pneumonia in infants and young children.4-6 This success generated interest in their potential use in adults for the preven-tion of pneumococcal CAP, which remains a major unmet medi-cal need. Consequently, the United States Food and Drug Administration granted accelerated approval of the 13-valen