title: Pandemic (H1N1) 2009 influenza in Canadian pediatric cancer and hematopoietic stem cell transplant patients.
abstract: BACKGROUND
  The impact of pandemic H1N1 influenza (pH1N1) virus in pediatric cancer is uncertain. The objectives of this study were to characterize the clinical course of pH1N1 and identify factors associated with severe outcomes.
  
  
  METHODS
  We conducted a Canadian multicenter retrospective review of children with cancer and stem cell transplant (SCT) recipients who were diagnosed with laboratory-confirmed pH1N1 infection between May 1, 2009 and January 31, 2010.
  
  
  RESULTS
  We identified 100 (19 in wave 1 and 81 in wave 2) cases of pH1N1 infection. Median age was 8.7 years. 71% had a hematologic malignancy, and 20% received SCT. Median duration of fever and illness was 2 and 12.5 days, respectively. 51 (51.5%) were hospitalized for a median of 5 days, with no deaths and only 1 requiring admission to the intensive care unit. Radiologically confirmed pneumonia was diagnosed in 10 (10%). Interruption of chemotherapy or conditioning occurred in 43 patients. In multivariable analyses, age <5 years (relative to ≥ 10 years) and neutropenia were associated with hospitalization while neutropenia was associated with pneumonia. Despite oseltamivir use in 89%, viral shedding was prolonged (median, 46 days) and often persisted after symptom resolution. However, an extended treatment course (>5 days) correlated with shortened duration of viral shedding (P=0.041).
  
  
  CONCLUSIONS
  pH1N1 infection in pediatric cancer and SCT patients infrequently caused complications but commonly interrupted cancer treatment. Persistent shedding of virus after illness resolution was common. Further research is needed to verify this finding as it could have implications for treatment guidelines and infection control practices.
authors.affiliation: Division of Infectious Diseases, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Dat
authors.initials: D
authors.lastname: Tran
authors.forename: Michelle
authors.initials: M
authors.lastname: Science
authors.forename: David
authors.initials: D
authors.lastname: Dix
authors.forename: Carol
authors.initials: C
authors.lastname: Portwine
authors.forename: Shayna
authors.initials: S
authors.lastname: Zelcer
authors.forename: Donna L
authors.initials: DL
authors.lastname: Johnston
authors.forename: Rochelle
authors.initials: R
authors.lastname: Yanofsky
authors.forename: Adam
authors.initials: A
authors.lastname: Gassas
authors.forename: Marie-Chantal
authors.initials: MC
authors.lastname: Ethier
authors.forename: Lillian
authors.initials: L
authors.lastname: Sung
mesh_terms: D000293:Adolescent; D000998:Antiviral Agents / Q000008:administration & dosage; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation; D006776:Hospitals, Pediatric; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000188:drug therapy / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D008297:Male; D009369:Neoplasms / Q000150:complications* / Q000628:therapy; D053139:Oseltamivir / Q000008:administration & dosage; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D017201:Virus Shedding
chemical_list: D000998:Antiviral Agents; D053139:Oseltamivir