title: Defining the Risk and Associated Morbidity and Mortality of Severe Respiratory Syncytial Virus Infection Among Preterm Infants Without Chronic Lung Disease or Congenital Heart Disease.
abstract: BACKGROUND
  The REGAL (RSV Evidence-a Geographical Archive of the Literature) series provide a comprehensive review of the published evidence in the field of respiratory syncytial virus (RSV) in Western countries over the last 20 years. This second publication covers the risk and burden of RSV infection in preterm infants born at <37 weeks' gestational age (wGA) without chronic lung disease or congenital heart disease.
  
  
  METHODS
  A systematic review was undertaken for articles published between January 1, 1995 and December 31, 2015. Studies reporting data for hospital visits/admissions for RSV infection among preterm infants as well as studies reporting RSV-associated morbidity, mortality, and risk factors were included. Study quality and strength of evidence (SOE) were graded using recognized criteria.
  
  
  RESULTS
  2469 studies were identified of which 85 were included. Preterm infants, particularly those born at lower wGA, tended to have higher RSV hospitalization (RSVH) rates compared with otherwise healthy term infants (high SOE). RSVH rates ranged from ~5 per 1000 children to >100 per 1000 children with the highest rates shown in the lowest gestational age infants (high SOE). Independent risk factors associated with RSVH include: proximity of birth to the RSV season, living with school-age siblings, smoking of mother during pregnancy or infant exposure to environmental smoking, reduced breast feeding, male sex, and familial atopy (asthma) (high SOE). Predictive models can identify 32/33-35 wGA infants at risk of RSVH (high SOE).
  
  
  CONCLUSIONS
  RSV infection remains a major burden on Western healthcare systems and is associated with significant morbidity. Further studies focusing on the prevalence and burden of RSV in different gestational age cohorts, the changing risk of RSVH during the first year of life, and on RSV-related mortality in preterm infants are needed to determine the true burden of disease.
  
  
  BACKGROUND
  AbbVie.
authors.affiliation: Hospital Clínic, Catedràtic de Pediatria, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Figueras-Aloy
authors.affiliation: Sant'Anna Hospital, Turin, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Manzoni
authors.affiliation: Department of Paediatrics (Neonatal Division), McMaster University, Hamilton, Canada.
authors.forename: Bosco
authors.initials: B
authors.lastname: Paes
authors.affiliation: University of Colorado School of Medicine, Aurora, Colorado, USA.
authors.forename: Eric A F
authors.initials: EA
authors.lastname: Simões
authors.affiliation: University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Louis
authors.initials: L
authors.lastname: Bont
authors.affiliation: Baylor College of Medicine, Texas Children's Hospital Houston, Texas, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Checchia
authors.affiliation: Necker University Hospital and Paris 5 University, Paris, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Fauroux
authors.affiliation: Hospital Clinic, Institut d'Investigacions Biomediques August Pi Suñer (IDIBAPS), Barcelona, Spain. carbonell@comb.cat.
authors.forename: Xavier
authors.initials: X
authors.lastname: Carbonell-Estrany
keywords: Burden; Gestational age; Hospitalization; Immunoprophylaxis; Preterm; Respiratory syncytial virus; Risk