Fig 1.
Flowchart of selection procedure.
The flowchart was based on the flowchart from the PRISMA group [17]. *Invasive pneumococcal disease (n = 11), not a primary research article (n = 7), vaccine or vaccinated group not of interest (n = 5), study protocol or rationale without results (n = 4), study design not of interest (n = 4), data from same source was presented in another article (n = 4), inadequate comparison group (n = 3), no relevant information (n = 3), data in children (n = 2), safety endpoint (n = 1), impact (n = 1). **Outcome other than any community-acquired pneumonia (CAP), pneumococcal CAP (pCAP) or nonbacteremic pCAP (n = 18), no vaccine effectiveness estimate provided (n = 7), estimates comparing receipt of both PPV23 and influenza vaccine with the receipt of influenza vaccine only (n = 2), CAP data from same source was presented in another article (n = 1).
Fig 2.
VE with most adjusted estimates for any-CAP in the general population, comparing PPV23 vaccinated with unvaccinated.
Fig 3.
Meta-analysis, stratified by availability of pediatric pneumococcal vaccine (PCV): VE with most adjusted estimates for hospitalization due to any-CAP in the general population, comparing PPV23 vaccinated with unvaccinated.
# weights from the random-effects model; *>70% for at least one dose; **45–64 years; ***65+ years.
Fig 4.
Meta-analysis, stratified by maximum time since vaccination: VE with most adjusted estimates for hospitalization due to any-CAP in the general population, comparing PPV23 vaccinated with unvaccinated.
*weights from the random-effects model; **45–64 years; ***65+ years.