Observational Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Pediatr. Nov 8, 2016; 5(4): 374-382
Published online Nov 8, 2016. doi: 10.5409/wjcp.v5.i4.374
Pandemic influenza 2009: Impact of vaccination coverage on critical illness in children, a Canada and France observational study
Olivier Fléchelles, Olivier Brissaud, Robert Fowler, Thierry Ducruet, Philippe Jouvet, the Pediatric Canadian Critical Care Trials Group H1N1 Collaborative and Groupe Francophone de Réanimation et Urgences Pédiatriques
Olivier Fléchelles, Pediatric and Neonatal ICU, MFME Hospital, Fort de France, 97261 Martinique, France
Olivier Fléchelles, Thierry Ducruet, Philippe Jouvet, Sainte-Justine Hospital, University of Montreal, Montreal, QC H3T 1C5, Canada
Olivier Brissaud, Pediatric and Neonatal ICU, Hôpital des Enfants, CHU Bordeaux, 33000 Bordeaux, France
Robert Fowler, Department of Critical Care Medicine, Sunnybrook Hospital, Toronto, ON M4N 3M5, Canada
Author contributions: Fléchelles O participated to the design, analysis and interpretation of data and drafted the article; Brissaud O participated to the design of the study, acquisition of data, interpretation of data and revised the manuscript critically for important intellectual; Fowler R and Ducruet T participated to the design of the study, interpretation of data and revised the manuscript critically; Jouvet P conceived, participated to the design of the study, analysed the results and draft the manuscript with Flechelles O; all authors gave final approval of the version of the manuscript submitted and agreed to act as guarantor of the work.
Supported by “Réseau en Santé Respiratoire du FRSQ”; and the Canadian Institutes of Health Research (CIHR) with the Public Health Agency of Canada.
Institutional review board statement: The participating institutions’ research ethics boards approved study procedures in each country.
Informed consent statement: The need for informed consent was waived given the non-interventional study design by the Institutional Review Boards (see the documents of the institutional review board statement).
Conflict-of-interest statement: The authors declare that they have no competing interests.
Data sharing statement: Dataset is available from the corresponding author at philippe.jouvet@umontreal.ca.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Philippe Jouvet, MD, PhD, Sainte-Justine Hospital, University of Montreal, 3175 Chemin Côte Sainte Catherine, Montreal, QC H3T 1C5, Canada. philippe.jouvet@umontreal.ca
Telephone: +1-514-3454927 Fax: +1-514-3427731
Received: June 27, 2016
Peer-review started: July 6, 2016
First decision: September 5, 2016
Revised: September 25, 2016
Accepted: October 22, 2016
Article in press: October 24, 2016
Published online: November 8, 2016
Processing time: 127 Days and 8.1 Hours
Abstract
AIM

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% vs 2% 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% vs 6.5%, P = 0.45, respectively), median invasive mechanical ventilation duration and mean PICU length of stay were shorter in Canada (4 d vs 6 d, P = 0.02 and 5.7 d vs 8.2 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).

CONCLUSION

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.

Keywords: Vaccine; Children; Intensive care; Critical care; Influenza; Pandemic

Core tip: This article is on a two national cohorts study from Canada and France of critically ill children during influenza pandemic and reports that: (1) critically ill French children were much less likely to have received vaccine prior to hospitalization against influenza A(H1N1)pdm09 in comparison to children in the Canadian populations; and (2) in Canada, where vaccination rate was higher, the risk of severe respiratory failure was less among those critically ill children receiving vaccine.