Abstract
SummaryBackgroundNon-invasive pneumococcal pneumonia causes significant morbidity and mortality in older adults. Understanding pneumococcal sero-epidemiology in adults ≥50 years is necessary to inform vaccination policies and the updating of pneumococcal vaccines.MethodsWe conducted a systematic review and random-effects meta-analysis to determine the proportion of community-acquired pneumonia (CAP) in people ≥50 years due to pneumococcus and the proportion caused by pneumococcal vaccine serotypes. We searched MEDLINE, EMBASE and PubMed from 1 January 1990 to 30 March 2021. Heterogeneity was explored by subgroup analysis according to a) patient group (stratified versus age) and depth of testing, b) detection/serotyping method, and c) continent. The protocol is registered with PROSPERO (CRD42020192002).FindingsTwenty-eight studies were included (34,216 patients). In the period 1–5 years after introduction of childhood PCV10/13 immunisation, 18% of CAP cases (95% CI 13–24%) were attributable to pneumococcus, with 49% (43–54%) of pneumococcal CAP due to PCV13 serotypes. The estimated proportion of pneumococcal CAP was highest in one study that used 24-valent serotype-specific urinary-antigen detection (ss-UAD)(30% [28–31%]), followed by studies based on diagnostic serology (28% [24–33%]), PCR (26% [15–37%]), ss-UAD14 (17% [13–22%]), and culture alone (14% [10–19%]). A higher estimate was observed in Europe (26% [21–30%] than North America (11% [9–12%](p<0·001). PCV13-serotype estimates were also influenced by serotyping methods.InterpretationNon-invasive pneumococcal CAP and vaccine-type pneumococcal CAP remains a burden in older adults despite widespread introduction of pneumococcal infant immunisation. Studies heavily reliant on ss-UADs restricted to vaccine-type serotypes may overestimate the proportion of potentially vaccine-preventable pneumococcal pneumonia. Sero-epidemiological data from low-income countries are lacking.
Highlights
Community-acquired pneumonia (CAP) is a significant cause of morbidity and mortality worldwide.[1,2] Streptococcus pneumoniae is the most commonly implicated bacterial pathogen,[3,4,5,6,7] and the spectrum of pneumococcal disease ranges from asymptomatic nasopharyngeal carriage through to localised infections and invasive pneumococcal disease (IPD), non-invasive pneumococcal pneumonia is the most common manifestation.[8]
Proportion of CAP due to Streptococcus pneumoniae Prior to introduction of childhood PCV10/13 immunisation, the pooled estimated proportion of CAP which was due to pneumococcus in people aged 50 years and above was 22%,15,25,27,42,44,46 ranging from 12% to 38%. (Supplementary Figure 1) Eleven studies included data from at least one year after the introduction of PCV10/13, with a pooled proportion of 18%, ranging from 9% to 32%
The estimated proportion of CAP due to pneumococcus was influenced by the testing method, with stratification according to pneumococcal detection method showing significant subgroup heterogeneity (p
Summary
Community-acquired pneumonia (CAP) is a significant cause of morbidity and mortality worldwide.[1,2] Streptococcus pneumoniae (pneumococcus) is the most commonly implicated bacterial pathogen,[3,4,5,6,7] and the spectrum of pneumococcal disease ranges from asymptomatic nasopharyngeal carriage through to localised infections and invasive pneumococcal disease (IPD), non-invasive pneumococcal pneumonia is the most common manifestation.[8] The Global Burden of Diseases Study estimated that in 2016 pneumococcal lower respiratory infections caused around 1¢2 million deaths worldwide and 197 million episodes.[9] The burden of pneumococcal disease follows a U-shaped curve, with greatest incidence and mortality in young children under 5 years and older adults aged 65 and above.[2,9,10]. Many countries around the world have established infant immunisation programmes against pneumococcal disease, most using www.thelancet.com Vol 44 Month February, 2022
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