Highlight: Update on seasonal influenza

The latest data from the Unified Influenza Network (combined data from the Grog, Sentinelles, and SCHS networks in Toulouse) for Week 9, February 27–March 4, 2012, show that the national incidence rate of consultations for influenza-like illness stands at 486 cases per 100,000 inhabitants but is decreasing compared to the previous week (the same trend is observed in Midi-Pyrénées, with 734 cases per 100,000 inhabitants in week 9); this suggests that the epidemic peak was likely reached this week, but confirmation will have to wait until next week. Incidence rates remain high across the entire country, however. Since the start of the epidemic, 150 severe cases have been reported in France, primarily among adults, and more than 500 clusters of acute respiratory infections have been reported by long-term care facilities for the elderly (EHPAD).

The INSEE mortality surveillance conducted at the InVS (analysis of mortality based on death certificates from municipalities with computerized civil registry offices—without information on medical causes of death) also showed that since week 6 of 2012 (February 6–12), an increase in the number of deaths from all causes was observable and remained pronounced during the following week. This increase in mortality particularly affects people over the age of 85. Virtually all regions are affected by the increase in mortality in this age group, although trends are more pronounced in southern and eastern France. This increase can be linked to several factors during this period, although it is not yet possible to specify the exact contribution of each factor to this increase: a period of intense and continuous cold weather between February 1 and 13, 2012, and a winter flu epidemic in full swing across the entire country, affecting a significant portion of the population, particularly the elderly. A slight decrease appeared to begin in week 8 (February 20–26, 2012). This trend is also observable in the Midi-Pyrénées region, with the number of deaths in week 9 lower than in the previous three weeks and comparable to that observed last year during the same period.