title: Pandemic influenza 2009: Impact of vaccination coverage on critical illness in children, a Canada and France observational study.
abstract: OBJECTIVE
  To study the impact of vaccination critical illness due to H1N1pdm09, we compared the incidence and severity of H1N1pdm09 infection in Canada and France.
  
  
  METHODS
  We studied two national cohorts that included children with documented H1N1pdm09 infection, admitted to a pediatric intensive care unit (PICU) in Canada and in France between October 1, 2009 and January 31, 2010.
  
  
  RESULTS
  Vaccination coverage prior to admission to PICUs was higher in Canada than in France (21%vs2% of children respectively,P< 0.001), and in both countries, vaccination coverage prior to admission of these critically ill patients was substantially lower than in the general pediatric population (P< 0.001). In Canada, 160 children (incidence = 2.6/100000 children) were hospitalized in PICU compared to 125 children (incidence = 1.1/100000) in France (P< 0.001). Mortality rates were similar in Canada and France (4.4%vs6.5%,P= 0.45, respectively), median invasive mechanical ventilation duration and mean PICU length of stay were shorter in Canada (4 dvs6 d,P= 0.02 and 5.7 dvs8.2 d,P= 0.03, respectively). H1N1pdm09 vaccination prior to PICU admission was associated with a decreased risk of requiring invasive mechanical ventilation (OR = 0.30, 95%CI: 0.11-0.83,P= 0.02).
  
  
  CONCLUSIONS
  The critical illness due to H1N1pdm09 had a higher incidence in Canada than in France. Critically ill children were less likely to have received vaccination prior to hospitalization in comparison to general population and children vaccinated had lower risk of ventilation.
authors.affiliation: Olivier Fléchelles, Pediatric and Neonatal ICU, MFME Hospital, Fort de France, 97261 Martinique, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Fléchelles
authors.affiliation: Olivier Fléchelles, Pediatric and Neonatal ICU, MFME Hospital, Fort de France, 97261 Martinique, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Brissaud
authors.affiliation: Olivier Fléchelles, Pediatric and Neonatal ICU, MFME Hospital, Fort de France, 97261 Martinique, France.
authors.forename: Robert
authors.initials: R
authors.lastname: Fowler
authors.affiliation: Olivier Fléchelles, Pediatric and Neonatal ICU, MFME Hospital, Fort de France, 97261 Martinique, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Ducruet
authors.affiliation: Olivier Fléchelles, Pediatric and Neonatal ICU, MFME Hospital, Fort de France, 97261 Martinique, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Jouvet
authors.affiliation: Olivier Fléchelles, Pediatric and Neonatal ICU, MFME Hospital, Fort de France, 97261 Martinique, France.
authors.lastname: The Pediatric Canadian Critical Care Trials Group H N Collaborative And Groupe Francophone de Réanimation Et Urgences Pédiatriques
keywords: Children; Critical care; Influenza; Intensive care; Pandemic; Vaccine