title: Potential impact of influenza A/H1N1 pandemic and hand-gels on acute diarrhea epidemic in France.
abstract: BACKGROUND
  The 2009 A/H1N1 influenza pandemic has received a great deal of attention from public health authorities. Our study examines whether this pandemic and the resulting public health measures could have impacted acute diarrhea, a prevalent, highly transmissible and historically monitored disease.
  
  
  METHODS
  Using augmentation procedures of national data for the previous five years (2004-2009), we estimated the expected timing and incidence of acute diarrhea in France in 2009-2010 and evaluated differences with the observed. We also reviewed national hand gels for the same period.
  
  
  RESULTS
  Number of episodes of acute diarrhea in France in 2009-2010 was significantly lower than expected until the third week of December (-24%, 95% CI [-36%; -9%]), then significantly higher (+40%, 95% CI [22%; 62%]), leading to a surplus of 574,440 episodes. The epidemic was delayed by 5 weeks with a peak 1.3 times higher than expected. Hand-gels sales inversely correlated with incidence of both influenza-like illness and acute diarrheal disease. Among individuals >65 yo, no excess cases of influenza and no excess rebound in acute diarrhea were observed, despite similar delay in the onset of the seasonal diarrheal epidemic.
  
  
  CONCLUSIONS
  Our results suggest that at least one endemic disease had an unexpected behavior in 2009-2010. Acute diarrhea seems to have been controlled during the beginning of the pandemic in all age groups, but later peaked higher than expected in the younger population. The all-age delay in seasonal onset seems partly attributable to hand-gels use, while the differential magnitude of the seasonal epidemic between young and old, concurrent for both influenza and acute diarrhea, is compatible with disease interaction.
authors.affiliation: École des hautes études en santé publique Rennes, Sorbonne Paris Cité, Paris, France ; UMR EPV Emergence des Pathologies Virales -190, Aix-Marseille University, Marseille, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Crépey
authors.forename: Mathilde
authors.initials: M
authors.lastname: Pivette
authors.forename: Moïse
authors.initials: M
authors.lastname: Desvarieux
mesh_terms: D003967:Diarrhea / Q000453:epidemiology*; D005602:France; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000472:pathogenicity; D007251:Influenza, Human / Q000453:epidemiology*