title: Burden of influenza, healthcare seeking behaviour and hygiene measures during the A(H1N1)2009 pandemic in France: a population based study.
abstract: BACKGROUND
  Influenza surveillance systems do not allow the identification of the true burden of illness caused by influenza in the community because they are restricted to consulting cases. A study was conducted to estimate the incidence and the burden of self-defined influenza, and to describe healthcare seeking behavior for self-defined influenza during the A(H1N1)2009 pandemic in the French population.
  
  
  METHODS
  We conducted a random-based retrospective cross-sectional telephone survey between May 2009 and April 2010 among a random sample of the French population.
  
  
  RESULTS
  For the 10 076 people included, 107 episodes of self-defined influenza were reported. The annual incidence of self-defined influenza was estimated at 13 942 cases per 100 000 inhabitants (CI95% 10 947 - 16 961), 62.1% (CI95% 50.5 - 72.5) of cases consulted a physician and 11.3% (CI95% 5.5 - 21.7) used a face mask. Following recommendations, 37.5% (CI95% 35.5 - 39.5) of people in the survey reported washing their hands more often during the pandemic season, and there was a positive association with being vaccinated against A(H1N1)2009 influenza, being a women, being a child (< 15 years) or living in a big city (≥ 100 000 inhabitants).
  
  
  CONCLUSIONS
  Self-defined influenza causes a significant burden of illness in the French population and is a frequent cause for consultation. These results allow a more accurate interpretation of influenza surveillance data and an opportunity to adapt future health education messages.
authors.affiliation: Department of infectious diseases, Institut de Veille Sanitaire (InVS) (French Institute for Public Health Surveillance), 12 rue de Val d'Osne, St Maurice Cedex, 94415, France.
authors.forename: Dieter
authors.initials: D
authors.lastname: Van Cauteren
authors.forename: Sophie
authors.initials: S
authors.lastname: Vaux
authors.forename: Henriette
authors.initials: H
authors.lastname: de Valk
authors.forename: Yann
authors.initials: Y
authors.lastname: Le Strat
authors.forename: Véronique
authors.initials: V
authors.lastname: Vaillant
authors.forename: Daniel
authors.initials: D
authors.lastname: Lévy-Bruhl
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D006920:Hygiene / Q000592:standards*; D015994:Incidence; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D058873:Pandemics / Q000517:prevention & control*; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D036301:Qualitative Research; D012189:Retrospective Studies; D055815:Young Adult