Polysaccharide Conjugate Vaccine against Pneumococcal Pneumonia in Adults

TLDR

Pneumococcal polysaccharide conjugate vaccines prevent disease in infants, but their efficacy against community‑acquired pneumonia in adults 65 years or older is unknown. The study evaluated PCV13 efficacy in preventing first episodes of vaccine‑type pneumococcal community‑acquired pneumonia, nonbacteremic and noninvasive community‑acquired pneumonia, and invasive pneumococcal disease in adults 65+. The trial used standard laboratory methods and a serotype‑specific urinary antigen detection assay to identify pneumococcal community‑acquired pneumonia and invasive disease, and performed per‑protocol analysis of first episodes. PCV13 reduced vaccine‑type pneumococcal community‑acquired pneumonia by 45.6%, nonbacteremic and noninvasive CAP by 45.0%, and invasive disease by 75.0%, with efficacy lasting nearly four years, while serious adverse events were similar to placebo and the vaccine did not prevent all‑cause community‑acquired pneumonia. The study was funded by Pfizer and registered under ClinicalTrials.gov NCT00744263.

Abstract

Pneumococcal polysaccharide conjugate vaccines prevent pneumococcal disease in infants, but their efficacy against pneumococcal community-acquired pneumonia in adults 65 years of age or older is unknown.In a randomized, double-blind, placebo-controlled trial involving 84,496 adults 65 years of age or older, we evaluated the efficacy of 13-valent polysaccharide conjugate vaccine (PCV13) in preventing first episodes of vaccine-type strains of pneumococcal community-acquired pneumonia, nonbacteremic and noninvasive pneumococcal community-acquired pneumonia, and invasive pneumococcal disease. Standard laboratory methods and a serotype-specific urinary antigen detection assay were used to identify community-acquired pneumonia and invasive pneumococcal disease.In the per-protocol analysis of first episodes of infections due to vaccine-type strains, community-acquired pneumonia occurred in 49 persons in the PCV13 group and 90 persons in the placebo group (vaccine efficacy, 45.6%; 95.2% confidence interval [CI], 21.8 to 62.5), nonbacteremic and noninvasive community-acquired pneumonia occurred in 33 persons in the PCV13 group and 60 persons in the placebo group (vaccine efficacy, 45.0%; 95.2% CI, 14.2 to 65.3), and invasive pneumococcal disease occurred in 7 persons in the PCV13 group and 28 persons in the placebo group (vaccine efficacy, 75.0%; 95% CI, 41.4 to 90.8). Efficacy persisted throughout the trial (mean follow-up, 3.97 years). In the modified intention-to-treat analysis, similar efficacy was observed (vaccine efficacy, 37.7%, 41.1%, and 75.8%, respectively), and community-acquired pneumonia occurred in 747 persons in the PCV13 group and 787 persons in placebo group (vaccine efficacy, 5.1%; 95% CI, -5.1 to 14.2). Numbers of serious adverse events and deaths were similar in the two groups, but there were more local reactions in the PCV13 group.Among older adults, PCV13 was effective in preventing vaccine-type pneumococcal, bacteremic, and nonbacteremic community-acquired pneumonia and vaccine-type invasive pneumococcal disease but not in preventing community-acquired pneumonia from any cause. (Funded by Pfizer; CAPITA ClinicalTrials.gov number NCT00744263.).