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

Unlabelled: 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.