title: Burden of Recurrent Respiratory Tract Infections in Children: A Prospective Cohort Study.
abstract: The burden of recurrent respiratory infections is unclear. We identified young children with recurrent respiratory infections in order to characterize the clinical manifestations, risk factors and short-term consequences.
  
  
  
  In this prospective cohort study, 1089 children were followed from birth to 2 years of age for respiratory infections by a daily symptom diary. Nasal swabs taken during respiratory infections were analyzed for viruses from 714 children. Nasopharyngeal swabs collected at 2 months of age were cultured for bacteria. The 10% of children with the highest number of annual respiratory illness days were defined to have recurrent respiratory tract infections.
  
  
  
  The 90th percentile in the number of annual respiratory illness days was 98. Children above this limit (n = 109) had a median of 9.6 acute respiratory infections per year. Rhinovirus was detected in 58% of their infections. Of the children with recurrent infections, 60% were diagnosed with at least 3 episodes of acute otitis media, 73% received at least 3 antibiotic treatments and 21% were hospitalized for an acute respiratory infection. Tympanostomy was performed for 35% and adenoidectomy for 13% of the children. Asthma was diagnosed in 12% by 24 months of age. Older siblings increased the risk of recurrent respiratory infections. Early nasopharyngeal colonization with Streptococcus pneumoniae was common in children who later developed recurrent infections.
  
  
  
  Children with recurrent respiratory infections frequently use health care services and antibiotics, undergo surgical procedures and are at risk for asthma in early life. Having older siblings increases the risk of recurrent infections.
authors.affiliation: From the *Department of Pediatrics and Adolescent Medicine, Turku University Hospital, Turku, Finland; †Turku Institute for Child and Youth Research, ‡Department of Medical Microbiology and Immunology, and §Department of Virology, University of Turku, Turku, Finland.
authors.forename: Laura
authors.initials: L
authors.lastname: Toivonen
authors.forename: Sinikka
authors.initials: S
authors.lastname: Karppinen
authors.forename: Linnea
authors.initials: L
authors.lastname: Schuez-Havupalo
authors.forename: Tamara
authors.initials: T
authors.lastname: Teros-Jaakkola
authors.forename: Juho
authors.initials: J
authors.lastname: Vuononvirta
authors.forename: Jussi
authors.initials: J
authors.lastname: Mertsola
authors.forename: Qiushui
authors.initials: Q
authors.lastname: He
authors.forename: Matti
authors.initials: M
authors.lastname: Waris
authors.forename: Ville
authors.initials: V
authors.lastname: Peltola
mesh_terms: D002675:Child, Preschool; D017281:Cost of Illness; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009296:Nasal Cavity / Q000821:virology; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000821:virology; D012229:Rhinovirus; D012307:Risk Factors; D014777:Virus Diseases / Q000453:epidemiology* / Q000821:virology