However , this quality assessment tool did not address all aspects related to study quality since we only looked into seven of these: study design, quality of control group, sample size, analysis method, bias, confounding factors and geographical spread of studies. (CI) for individual risk factors. == Results == We identified 20 studies (3 were unpublished data) with good quality that investigated 18 risk factors for RSVassociated ALRI in children younger than five years old. Among them, 8 risk factors were significantly associated with RSVassociated ALRI. The metaestimates of their odds ratio (ORs) with corresponding 95% confidence intervals (CI) are prematurity 1 . 96 (95% CI 1 . 442. 67), low birth weight 1 . 91 (95% CI 1 . 452. 53), being male 1 . 23 (95% CI 1 . 131. 33), having siblings 1 . 60 (95% CI 1 . 321. 95), maternal smoking 1 . 36 (95% CI 1 . 241. 50), history of atopy 1 . 47 (95% CI 1 . 161. 87), no breastfeeding 2 . 24 (95% CI 1 . 563. 20) and crowding 1 . 94 (95% CI 1 . 292. 93). Although there were insufficient studies available to generate a metaestimate for HIV, all articles (irrespective of quality scores) reported significant associations between HIV and RSVassociated ALRI. == Conclusions == This study presents a comprehensive report of the strength of association between various sociodemographic risk factors and RSVassociated ALRI in young children. Some of these amenable risk factors are similar to those that have been identified for (all cause) ALRI and thus, in addition to the future impact of novel Rabbit polyclonal to ACMSD RSV vaccines, national action against ALRI risk factors as part of national control programmes can be expected to reduce burden of disease from BMPS RSV. Further research which identifies, accesses and analyses additional unpublished RSV data sets could further improve the precision of these estimates. Acute lower respiratory infection (ALRI), including pneumonia and bronchiolitis, remains the leading cause of childhood hospitalisation and mortality [1], primarily within developing countries [2]. It is estimated that in 2010, there were about 120. 4 million episodes of ALRI and about 14. 1 million respective episodes of severe ALRI in children younger than 5 years [3]. It is also estimated that there were 1 . 4 million pneumonia deaths in this age group that year (which decreased to 936 000 in 2013) [4]. Globally, respiratory syncytial virus (RSV) is the most common pathogen identified in young children with ALRI, as well as an important cause of hospital admissions [5]. It is estimated that in 2005 there were about 33. 8 million new episodes of ALRI which were RSV positive in children younger than 5 years and about 10% of these were severe enough to warrant hospitalisation. It is also estimated that RSV attributable mortality in children younger than 5 years was around 53 255 inhospital deaths and up to 199 260 overall deaths globally in 2005, with 99% of these occurring in developing countries. RSV is known to be more likely to have a severe BMPS outcome in children with certain preexisting chronic medical conditions, resulting in higher rate of hospitalisation and higher risk of death. A case-control study in southwest Alaska indicated that underlying medical conditions, such as prematurity, chronic lung disease and heart disease, were associated with an increased risk of RSV hospitalisation [6]. Another systematic review reported BMPS that the case fatality ratio among children hospitalised with RSV infection was higher in children with chronic lung disease, congenital heart disease or prematurity, compared to otherwise healthy children [7]. The high incidence of RSV infection, as well as its potentially severe outcome, makes it important to identify and prioritise children at high risk of developing RSVassociated ALRI. To date, there has been only one systematic review published over a decade ago that assessed the strength of association between various risk factors and RSVassociated ALRI [8]. There have been no recent comprehensive systematic reviews that included the recent literatures reporting the association of various putative risk factors and RSVassociated ALRI in young children. Therefore , we conducted a systematic review to identify studies investigating the association between potential risk factors and RSVassociated ALRI in children younger than five years. We aimed to assess the quality of available evidence and present summary metaestimates of the strength of association between multiple risk factors and RSVassociated ALRI BMPS to identify targeted prevention strategies. == METHODS == == Search strategy and selection criteria == We conducted a systematic review according to the PRISMA guidelines. The search was conducted across the following electronic databases: Medline, Embase, Global Health and LILACS. The search terms used are detailed.
