title: Impact of pandemic A/H1N1/2009 influenza on children and their families: comparison with seasonal A/H1N1 and A/H3N2 influenza viruses.
abstract: OBJECTIVE
  To make a direct comparison between the total burden of pandemic influenza and that of other seasonal influenza A viral subtypes in otherwise healthy children.
  
  
  METHODS
  The total clinical and socioeconomic burden of pandemic A/H1N1/2009 influenza was compared with that of seasonal influenza A viral subtypes in 389 otherwise healthy children with A/H1N1/2009, 126 with seasonal A/H1N1 and 486 with seasonal A/H3N2 infection referred to the Emergency Room and hospitalised in the in-patient units of a large, university-based paediatric hospital. Influenza diagnosis was confirmed by real-time polymerase chain reaction.
  
  
  RESULTS
  Regardless of age or gender, the variables significantly associated with pandemic A/H1N1/2009 and seasonal A/H3N2 infection were a diagnosis of lower respiratory tract infection upon clinical presentation, the need for hospitalisation, hospitalisation for ≥7 days, school absences of ≥7 days, the need for aerosol therapy, the household development of a disease similar to that of the infected child, and the need for additional household medical visits and antibiotic prescriptions (p < 0.001). A longer period of hospitalisation and lost school days seemed to be associated with pandemic A/H1N1/2009 infection (p < 0.01).
  
  
  CONCLUSIONS
  Perceived symptom severity and the risk of serious outcomes are similar in children with influenza due to pandemic A/H1N1/2009 or seasonal A/H3N2 influenza, but both of these viruses seem to have a greater clinical and socioeconomic impact than seasonal A/H1N1 virus, regardless of the patients' age or gender.
authors.affiliation: Department of Maternal and Paediatric Sciences, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Commenda 9, 20122 Milano, Italy.
authors.forename: Susanna
authors.initials: S
authors.lastname: Esposito
authors.forename: Claudio Giuseppe
authors.initials: CG
authors.lastname: Molteni
authors.forename: Cristina
authors.initials: C
authors.lastname: Daleno
authors.forename: Claudia
authors.initials: C
authors.lastname: Tagliabue
authors.forename: Irene
authors.initials: I
authors.lastname: Picciolli
authors.forename: Alessia
authors.initials: A
authors.lastname: Scala
authors.forename: Claudio
authors.initials: C
authors.lastname: Pelucchi
authors.forename: Emilio
authors.initials: E
authors.lastname: Fossali
authors.forename: Nicola
authors.initials: N
authors.lastname: Principi
mesh_terms: D002648:Child; D002675:Child, Preschool; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006776:Hospitals, Pediatric; D006785:Hospitals, University; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D053122:Influenza A Virus, H3N2 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology / Q000473:pathology* / Q000821:virology*; D008297:Male; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction; D012720:Severity of Illness Index; D012959:Socioeconomic Factors