[A(H1N1) influenza surveillance in the French armed forces: adapting the surveillance systems to the pandemic setting]

Abstract

Objectives: An outbreak of A(H1N1) virus influenza, detected in Mexico during April 2009, spread around the world in nine weeks. French armed forces had to adapt their epidemiological surveillance systems to this pandemic. Our aim was to present surveillance results.

Design: There are two influenza surveillance systems in French armed forces: one permanent throughout the year and one seasonal, the Military influenza surveillance system (SMOG). The pandemic threat led to an early reactivation of SMOG, before the initiation of a daily surveillance system specifically dedicated to A(H1N1) influenza.

Results: In metropolitan France, the increase of respiratory infections was observed as of September 2009, with a maximum of 401 cases for 100,000 at the beginning of December according to SMOG. The estimated rate of consultations related to A(H1N1) influenza ranged between 46 and 65 cases for 100,000. For military units operating outside of metropolitan France, a peak of incidence was observed in August (400 cases for 100,000).

Conclusion: The trends observed by influenza military surveillance networks were compatible with French ones. Concerning French forces in operations, the increase of incidence observed in August was the consequence of the influenza outbreak in the Southern hemisphere. Estimations of consultations rate related to A(H1N1) influenza, ranged between 127 and 194 cases for 100,000 at the beginning of December, lower than the national rate (1321 cases for 100,000), a consequence of the age pyramid in the military population.