title: The effectiveness of pneumococcal polysaccharide vaccine 23 (PPV23) in the general population of 50 years of age and older: A systematic review and meta-analysis.
abstract: Two pneumococcal vaccines currently exist and have been recommended for the prevention of pneumococcal infection in adults 65 years of age and older: the 23-valent polysaccharide (PPV23) and the conjugate 13-valent (PCV13) vaccine.
  
  
  OBJECTIVE
  To evaluate and summarize the results from all studies reporting on the vaccine effectiveness of PPV23 in preventing invasive pneumococcal disease (IPD) and community-acquired pneumonia (CAP) in individuals over the age of 50.
  
  
  METHODS
  Systematic database searches were completed in PubMed, Medline, Embase, CINAHL, Web of Science, and Cochrane. Google Scholar and hand searches of seminal articles and past systematic reviews were employed. Studies were included if they independently evaluated the effect of PPV23 on IPD and/or CAP in adults (50+). Data extraction and quality assessment were both completed independently by two researchers. Quality was assessed using the National Advisory Committee on Immunization methodology for quality assessment. All conflicts were resolved by consensus.
  
  
  RESULTS
  The vaccine effectiveness for PPV23 in preventing IPD was 50% (95% CI: 21%-69%) for cohort studies and 54% (95% CI: 32%-69%) for case-control studies. The VE estimates for CAP were 4% (95% CI: -26%-26%) for trials, 17% (95% CI: -26%-45%) for cohort studies, and 7% (95% CI: -10%-21%) for case-control studies.
  
  
  CONCLUSIONS
  The vaccine effectiveness of PPV23 in preventing IPD and all-cause CAP was consistent with past systematic reviews and similar to the estimates that were reported in the CAPiTA trial evaluating the vaccine effectiveness of PCV13. Consistent benefits were also reported across ecological studies and reports of surveillance data for the general population 50 years and older. The results suggests that the current practice of vaccinating the adults 65 years of age and older with PPV23 would have similar benefits to PCV13 in preventing potential cases of all-serotype IPD and all-cause CAP.
authors.affiliation: Department of Epidemiology, Biostatistics & Occupational Health, McGill University, Montreal, QC, Canada; MUHC Vaccine Study Centre - Research Institute, McGill University Health Centre, Montreal, QC, Canada.
authors.forename: Hannah
authors.initials: H
authors.lastname: Kraicer-Melamed
authors.affiliation: Department of Epidemiology, Biostatistics & Occupational Health, McGill University, Montreal, QC, Canada; MUHC Vaccine Study Centre - Research Institute, McGill University Health Centre, Montreal, QC, Canada.
authors.forename: Shauna
authors.initials: S
authors.lastname: O'Donnell
authors.affiliation: Department of Epidemiology, Biostatistics & Occupational Health, McGill University, Montreal, QC, Canada; MUHC Vaccine Study Centre - Research Institute, McGill University Health Centre, Montreal, QC, Canada; Department of Pediatrics, Division of Infectious Diseases, McGill University, Montreal, QC, Canada; Quebec Institute of Public Health, Montreal, QC, Canada. Electronic address: caroline.quach@mcgill.ca.
authors.forename: Caroline
authors.initials: C
authors.lastname: Quach
mesh_terms: D000368:Aged; D017714:Community-Acquired Infections / Q000382:microbiology / Q000517:prevention & control; D000068598:Data Accuracy; D006801:Humans; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000627:therapeutic use*; D018410:Pneumonia, Bacterial / Q000517:prevention & control*
chemical_list: C414006:23-valent pneumococcal capsular polysaccharide vaccine; D022242:Pneumococcal Vaccines
keywords: 23-Valent pneumococcal polysaccharide vaccine; Effectiveness; Elderly; Systematic review, Meta-analysis