title: Respiratory syncytial virus-associated hospitalizations among children less than 24 months of age.
abstract: BACKGROUND
  Respiratory syncytial virus (RSV) infection is a leading cause of hospitalization among infants. However, estimates of the RSV hospitalization burden have varied, and precision has been limited by the use of age strata grouped in blocks of 6 to ≥ 12 months.
  
  
  METHODS
  We analyzed data from a 5-year, prospective, population-based surveillance for young children who were hospitalized with laboratory-confirmed (reverse-transcriptase polymerase chain reaction) RSV acute respiratory illness (ARI) during October through March 2000-2005. The total population at risk was stratified by month of age by birth certificate information to yield hospitalization rates.
  
  
  RESULTS
  There were 559 (26%) RSV-infected children among the 2149 enrolled children hospitalized with ARI (85% of all eligible children with ARI). The average RSV hospitalization rate was 5.2 per 1000 children <24 months old. The highest age-specific rate was in infants 1 month old (25.9 per 1000 children). Infants ≤ 2 months of age, who comprised 44% of RSV-hospitalized children, had a hospitalization rate of 17.9 per 1000 children. Most children (79%) were previously healthy. Very preterm infants (<30 weeks' gestation) accounted for only 3% of RSV cases but had RSV hospitalization rates 3 times that of term infants.
  
  
  CONCLUSIONS
  Young infants, especially those who were 1 month old, were at greatest risk of RSV hospitalization. Four-fifths of RSV-hospitalized infants were previously healthy. To substantially reduce the burden of RSV hospitalizations, effective general preventive strategies will be required for all young infants, not just those with risk factors.
authors.affiliation: Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
authors.forename: Caroline Breese
authors.initials: CB
authors.lastname: Hall
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Weinberg
authors.forename: Aaron K
authors.initials: AK
authors.lastname: Blumkin
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Edwards
authors.forename: Mary A
authors.initials: MA
authors.lastname: Staat
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Schultz
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Poehling
authors.forename: Peter G
authors.initials: PG
authors.lastname: Szilagyi
authors.forename: Marie R
authors.initials: MR
authors.lastname: Griffin
authors.forename: John V
authors.initials: JV
authors.lastname: Williams
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Zhu
authors.forename: Carlos G
authors.initials: CG
authors.lastname: Grijalva
authors.forename: Mila M
authors.initials: MM
authors.lastname: Prill
authors.forename: Marika K
authors.initials: MK
authors.lastname: Iwane
mesh_terms: D000367:Age Factors; D002675:Child, Preschool; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000175:diagnosis / Q000453:epidemiology; D019102:Infant, Very Low Birth Weight; D008297:Male; D009518:New York; D011159:Population Surveillance; D011446:Prospective Studies; D018357:Respiratory Syncytial Virus Infections / Q000175:diagnosis / Q000453:epidemiology*
keywords: acute respiratory illness; respiratory syncytial virus