Elsevier

The Lancet

Volume 374, Issue 9693, 12–18 September 2009, Pages 893-902
The Lancet

Articles
Burden of disease caused by Streptococcus pneumoniae in children younger than 5 years: global estimates

https://doi.org/10.1016/S0140-6736(09)61204-6Get rights and content

Summary

Background

Streptococcus pneumoniae is a leading cause of bacterial pneumonia, meningitis, and sepsis in children worldwide. However, many countries lack national estimates of disease burden. Effective interventions are available, including pneumococcal conjugate vaccine and case management. To support local and global policy decisions on pneumococcal disease prevention and treatment, we estimated country-specific incidence of serious cases and deaths in children younger than 5 years.

Methods

We measured the burden of pneumococcal pneumonia by applying the proportion of pneumonia cases caused by S pneumoniae derived from efficacy estimates from vaccine trials to WHO country-specific estimates of all-cause pneumonia cases and deaths. We also estimated burden of meningitis and non-pneumonia, non-meningitis invasive disease using disease incidence and case-fatality data from a systematic literature review. When high-quality data were available from a country, these were used for national estimates. Otherwise, estimates were based on data from neighbouring countries with similar child mortality. Estimates were adjusted for HIV prevalence and access to care and, when applicable, use of vaccine against Haemophilus influenzae type b.

Findings

In 2000, about 14·5 million episodes of serious pneumococcal disease (uncertainty range 11·1–18·0 million) were estimated to occur. Pneumococcal disease caused about 826 000 deaths (582 000–926 000) in children aged 1–59 months, of which 91 000 (63 000–102 000) were in HIV-positive and 735 000 (519 000–825 000) in HIV-negative children. Of the deaths in HIV-negative children, over 61% (449 000 [316 000–501 000]) occurred in ten African and Asian countries.

Interpretation

S pneumoniae causes around 11% (8–12%) of all deaths in children aged 1–59 months (excluding pneumococcal deaths in HIV-positive children). Achievement of the UN Millennium Development Goal 4 for child mortality reduction can be accelerated by prevention and treatment of pneumococcal disease, especially in regions of the world with the greatest burden.

Funding

GAVI Alliance and the Vaccine Fund.

Introduction

Streptococcus pneumoniae is a leading cause of bacterial pneumonia, meningitis, and sepsis in children. Recent estimates of child deaths caused by S pneumoniae range from 700 000 to 1 million every year worldwide.1, 2, 3

Since resources for child survival are increasing, estimates of pneumococcal disease burden based on comprehensive, clear, and rigorous methods are needed. Although global estimates are valuable for international institutions and global initiatives, they have limited use for national policy makers. Progress in pneumonia case and death prevention will be facilitated by cause-specific estimates that help local and regional policy makers to prioritise interventions, such as vaccines or antibiotic treatments, specific for particular pneumonia causes.

We estimated the burden of serious pneumococcal cases and deaths in children younger than 5 years for the year 2000 at global, regional, sub-regional, and country levels by systematic, transparent methods (webappendix), including a comprehensive literature review.4

Section snippets

Methods

We used distinct methods to estimate pneumococcal disease burden from three serious clinical syndromes: meningitis, pneumonia, and non-pneumonia, non-meningitis invasive disease (defined as isolation of S pneumoniae from a normally sterile body fluid). Methods are described in detail in the webappendix pp 3–9; however, here we provide a concise description of the main components.

To obtain data for the models of meningitis and non-pneumonia, non-meningitis invasive disease, we did a

Results

The comprehensive literature review4 yielded 156 studies with data for the meningitis or the non-pneumonia, non-meningitis disease models after application of the inclusion, exclusion, and quality criteria (webappendix pp 30–37). All regions, except southeast Asia, had at least some data for pneumococcal meningitis incidence. All regions, except eastern Mediterranean, had data for pneumococcal meningitis case-fatality ratio (table 1). Overall, 15% of countries had pneumococcal meningitis

Discussion

735 000 pneumococcal deaths (519 000–825 000) in HIV-negative children account for 11% (8–12%) of 6·6 million total deaths in children aged 1–59 months19, 21 and for 7% (5–8%) of 10·6 million deaths in children younger than 5 years including neonatal deaths.19 Although these numbers represent the most rigorous estimate of child deaths caused by S pneumoniae, they are probably an underestimate. Surveillance in high-mortality developing countries usually under-detects bacterial meningitis and

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