title: Clinical characteristics and outcomes in children hospitalised with pandemic influenza A/H1N1/09 virus infection – a nationwide survey by the Pediatric Infectious Diseases Group of Switzerland.
abstract: OBJECTIVE
  To describe all patients admitted to children's hospitals in Switzerland with a diagnosis of influenza A/H1N1/09 virus infection during the 2009 influenza pandemic, and to analyse their characteristics, predictors of complications, and outcome.
  
  
  METHODS
  All patients ≤18-years-old hospitalised in eleven children's hospitals in Switzerland between June 2009 and January 2010 with a positive influenza A/H1N1/09 reverse transcriptase polymerase chain reaction (RT-PCR) from a nasopharyngeal specimen were included.
  
  
  RESULTS
  There were 326 PCR-confirmed patients of whom 189 (58%) were younger than 5 years of age, and 126 (38.7%) had one or more pre-existing medical condition. Fever (median 39.1 °C) was the most common sign (85.6% of all patients), while feeding problems (p = 0.003) and febrile seizures (p = 0.016) were significantly more frequent in children under 5 years. In 142 (43.6%) patients there was clinical suspicion of a concomitant bacterial infection, which was confirmed in 36 patients (11%). However, severe bacterial infection was observed in 4% of patients. One third (n = 108, 33.1%) of the patients were treated with oseltamivir, 64 (59.3%, or 20% overall) within 48 hours of onset of symptoms. Almost half of the patients (45.1%) received antibiotics for a median of 7 days. Twenty patients (6.1%) required intensive care, mostly for complicated pneumonia (50%) without an underlying medical condition. The median duration of hospitalisation was 2 days (range 0-39) for 304 patients. Two children (<15 months of age with underlying disease) died.
  
  
  CONCLUSIONS
  Although pandemic influenza A/H1N1/09 virus infection in children is mostly mild, it can be severe, regardless of past history or underlying disease.
authors.affiliation: Department of Paediatrics, University Hospitals of Geneva and Medical School of Geneva, Switzerland.
authors.forename: Andres
authors.initials: A
authors.lastname: Hagerman
authors.affiliation: Department of Paediatrics, University Hospitals of Geneva and Medical School of Geneva, Switzerland.
authors.forename: Klara M
authors.initials: KM
authors.lastname: Posfay-Barbe
authors.affiliation: University Children's Hospital Bern, Switzerland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Duppenthaler
authors.affiliation: University Children's Hospital (UKBB) Basel, Switzerland.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Heininger
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Children's Hospital Zurich, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Berger
authors.affiliation: Pediatric Infectious Diseases Group Switzerland (PIGS, www.pigs.ch) Influenza study group members are: Andrea Lehmann (Children's Hospital Aarau), Ulrich Heininger and Gurli Bär (University Children's Hospital Basel), Andrea Duppenthaler and Sara Ber.
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D000998:Antiviral Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D005260:Female; D006776:Hospitals, Pediatric / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000188:drug therapy / Q000453:epidemiology* / Q000503:physiopathology; D015278:Intensive Care Units, Pediatric / Q000706:statistics & numerical data; D007902:Length of Stay; D008297:Male; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013557:Switzerland / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D000998:Antiviral Agents