ArticlesGlobal burden of acute lower respiratory infections due to respiratory syncytial virus in young children: a systematic review and meta-analysis
Introduction
Acute lower respiratory infection (ALRI) is the leading cause of global child mortality.1, 2 Respiratory syncytial virus (RSV) is believed to be the most important viral pathogen causing ALRI in young children, although its contribution to ALRI deaths is uncertain.3, 4, 5 Many data for incidence of and mortality from RSV-associated ALRI in developing countries remain unpublished. Therefore, we formed an RSV study group to supplement a systematic literature review with unpublished data. No global or regional estimates have been made previously of the burden of RSV-associated ALRI in children. Previous reviews have focused either on developing countries4, 6 or industrialised countries.7 We aimed to estimate the burden of disease worldwide due to RSV-associated ALRI in children younger than 5 years for 2005. We estimated only the ALRI component of the burden due to RSV infection because the main costs of RSV disease relate to health-service use for ALRI, and first-generation RSV vaccines are likely to protect against ALRI.3 This report is especially timely in view of the development of candidate vaccines that are sufficiently attenuated yet immunogenic in infants,8, 9, 10 and the increased funding for development and implementation of novel vaccines in developing countries that is available through the Global Alliance for Vaccines and Immunisation. We also aimed to emphasise important gaps in knowledge and to provide information about potential sites for vaccine trials.
Section snippets
Search strategy and selection criteria
We did a systematic literature review using a combination of search terms (webappendix pp 3–4), hand searching of online journals, and scanning of reference lists of identified citations. The search was limited to Medline (Ovid), Embase, CINAHL, Global Health, Web of Science, WHOLIS, LILACS, IndMed, and the grey literature (SIGLE) databases and to studies published between January, 1995, and June, 2009. Panel 1 shows eligibility criteria. No language or publication restrictions were applied. We
Results
We identified 36 studies with suitable data (figure 2): 19 published population-based studies reporting incidence of RSV-associated severe or non-severe ALRI in populations under surveillance; seven published studies estimating incidence on the basis of hospital discharge records or laboratory diagnosis reports and a census-based denominator of children at risk; and unpublished data from ten population-based studies, again reporting a clear denominator of children at risk (figure 3, table 1).18
Discussion
We estimated that in 2005, at least 33·8 (95% CI 19·3–46·2) million episodes of RSV-associated ALRI occurred worldwide in children younger than 5 years, with incidence in developing countries more than twice that of industrialised countries. This estimate represents roughly 22% of all episodes of ALRI in young children. By comparison, 13·8 (10·8–17·2) million episodes of pneumococcal pneumonia and 7·9 (7·2–12·9) million episodes of Haemophilus influenzae type b pneumonia occurred in the same
References (56)
- et al.
WHO estimates of the causes of death in children
Lancet
(2005) Respiratory syncytial virus infection
Lancet
(1999)- et al.
An update on respiratory syncytial virus epidemiology: a developed country perspective
Respir Med
(2002) - et al.
Rates of hospitalization for respiratory syncytial virus infection among children in Medicaid
J Pediatr
(2000) - et al.
Burden of disease caused by Streptococcus pneumoniae in children younger than 5 years: global estimates
Lancet
(2009) - et al.
Burden of disease caused by Haemophilus influenzae type b in children younger than 5 years: global estimates
Lancet
(2009) - et al.
Improved oxygen systems for childhood pneumonia: a multihospital effectiveness study in Papua New Guinea
Lancet
(2008) - et al.
Respiratory syncytial virus prophylaxis—the story so far
Respir Med
(2002) - et al.
Epidemiology and etiology of clinical pneumonia
Bull World Health Organ
(2008) - et al.