title: Population-based incidence of human metapneumovirus infection among hospitalized children.
abstract: BACKGROUND
  Human metapneumovirus (HMPV) is a leading cause of acute respiratory illness (ARI) in children. Population-based incidence rates and comprehensive clinical characterizations of disease have not been established.
  
  
  METHODS
  We conducted population-based prospective surveillance for 2 years in 2 US counties of HMPV infection among children <5 years old who were hospitalized with ARI or fever. Nasal and throat specimens obtained with swabs were tested for HMPV by real-time reverse-transcription polymerase chain reaction and genotyped.
  
  
  RESULTS
  Forty-two (3.8%) of 1104 children tested positive for HMPV. The overall annual rate of HMPV-associated hospitalizations per 1000 children <5 years old was 1.2 (95% confidence interval [CI], 0.9-1.6). This rate was highest among infants 0-5 months old (4.9 per 1000 [95% CI, 2.9-7.2]), followed by children 6-11 months old (2.9 per 1000 [95% CI, 1.4-4.7]). The annual rate of hospitalization for HMPV infection was less than that for respiratory syncytial virus infection but similar to that for influenza and parainfluenza virus 3 infection in all age groups. The mean age of children hospitalized with HMPV infection was 6 months. Bronchiolitis, pneumonia, and asthma were the most common diagnoses among children with HMPV infection. All 4 HMPV subgroups were detected during both years at both sites. HPMV infection was most prominent from March through May.
  
  
  CONCLUSIONS
  HMPV was detected in 3.8% of children hospitalized with ARI or fever, with a population incidence similar to that of influenza virus and parainfluenza virus 3.
authors.affiliation: Department of Pediatrics, Vanderbilt University Schoolof Medicine, and Monroe Carell Jr Children's Hospital at Vanderbilt, Nashville, Tennessee 37232-2581, USA. john.williams@vanderbilt.edu
authors.forename: John V
authors.initials: JV
authors.lastname: Williams
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Edwards
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Weinberg
authors.forename: Marie R
authors.initials: MR
authors.lastname: Griffin
authors.forename: Caroline B
authors.initials: CB
authors.lastname: Hall
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Zhu
authors.forename: Peter G
authors.initials: PG
authors.lastname: Szilagyi
authors.forename: Chiaoyin K
authors.initials: CK
authors.lastname: Wang
authors.forename: Chin-Fen
authors.initials: CF
authors.lastname: Yang
authors.forename: David
authors.initials: D
authors.lastname: Silva
authors.forename: Dan
authors.initials: D
authors.lastname: Ye
authors.forename: Richard R
authors.initials: RR
authors.lastname: Spaete
authors.forename: James E
authors.initials: JE
authors.lastname: Crowe
mesh_terms: D002673:Child, Hospitalized; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D029121:Metapneumovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D009666:Nose / Q000821:virology; D018184:Paramyxoviridae Infections / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D010614:Pharynx / Q000821:virology; D011446:Prospective Studies; D012367:RNA, Viral / Q000235:genetics; D012140:Respiratory Tract Diseases / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014481:United States
chemical_list: D012367:RNA, Viral
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