title: Comparison of risk factors for human metapneumovirus and respiratory syncytial virus disease severity in young children.
abstract: BACKGROUND
  Human metapneumovirus (hMPV) and respiratory syncytial virus (RSV) are leading pediatric pathogens. However, risk factors for severe hMPV disease remain unknown. We comparatively assessed environmental, host, and viral determinants for severe hMPV and RSV infections.
  
  
  METHODS
  We studied a prospective cohort of >1000 children aged <3 years hospitalized in or presenting to a pediatric clinic for acute respiratory infection. We collected clinical data at enrollment and 1-month follow-up and tested nasopharyngeal secretions for respiratory viruses. Disease severity was defined as hospitalization and was also assessed with a severity score (1 point/variable) calculated on the basis of fraction of inhaled O(2) ≥ 30%, hospitalization >5 days, and pediatric intensive care unit admission.
  
  
  RESULTS
  hMPV was identified in 58 of 305 outpatient children (19.0%) and 69 of 734 hospitalized children (9.4%), second only to RSV (48.2% and 63.6%, respectively). In multivariate regression analysis of hMPV cases, age <6 months and household crowding were associated with hospitalization. Among hospitalized patients, risk factors for severe hMPV disease were female sex, prematurity, and genotype B infection. Age <6 months, comorbidities, and household crowding were risk factors for RSV hospitalization; breast-feeding and viral coinfection were protective. Age <6 months and prematurity were associated with severe RSV cases among hospitalized children.
  
  
  CONCLUSIONS
  hMPV and RSV severity risk factors may differ slightly. These findings will inform hMPV prevention strategies.
authors.affiliation: Centre de recherche en infectiologie de l'Université Laval, Centre de recherche du CHUQ, Quebec, Canada.
authors.forename: Jesse
authors.initials: J
authors.lastname: Papenburg
authors.forename: Marie-Ève
authors.initials: MÈ
authors.lastname: Hamelin
authors.forename: Najwa
authors.initials: N
authors.lastname: Ouhoummane
authors.forename: Julie
authors.initials: J
authors.lastname: Carbonneau
authors.forename: Manale
authors.initials: M
authors.lastname: Ouakki
authors.forename: Frédéric
authors.initials: F
authors.lastname: Raymond
authors.forename: Lynda
authors.initials: L
authors.lastname: Robitaille
authors.forename: Jacques
authors.initials: J
authors.lastname: Corbeil
authors.forename: Georges
authors.initials: G
authors.lastname: Caouette
authors.forename: Lyne
authors.initials: L
authors.lastname: Frenette
authors.forename: Gaston
authors.initials: G
authors.lastname: De Serres
authors.forename: Guy
authors.initials: G
authors.lastname: Boivin
mesh_terms: D000367:Age Factors; D002675:Child, Preschool; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000473:pathology / Q000821:virology; D003441:Crowding; D005191:Family Characteristics; D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D029121:Metapneumovirus; D018184:Paramyxoviridae Infections / Q000453:epidemiology / Q000473:pathology* / Q000821:virology; D011446:Prospective Studies; D011792:Quebec / Q000453:epidemiology; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology / Q000473:pathology* / Q000821:virology; D012136:Respiratory Syncytial Viruses; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors