Surveillance of Severe Influenza Cases in Intensive Care Units for the 2015–2016 Season In mainland France last winter, the community-based influenza epidemic began in mid-January and lasted for 9 weeks, characterized by the predominant circulation of influenza A(H3N2) viruses, some of which were not well covered by the vaccine. The epidemic had a significant impact, particularly on the elderly, and the excess mortality from all causes estimated during the epidemic period was 18,300 deaths (the proportion attributable to influenza has not yet been determined).The number of severe influenza cases nationwide (1,609 cases) was the highest ever recorded since 2009, and nearly half of them were aged 65 and older. Severe cases were primarily infected with the A virus (83%). In Midi-Pyrénées, the number of reported severe influenza cases was also the highest since the implementation of this surveillance in 2009 (83 severe cases). It therefore seems important for the InVS to resume surveillance of severe influenza cases in intensive care (adult and pediatric) for the 2015-16 season in week 45 (November 2). In practice, the procedure is identical to last year’s. All probable (as determined by the hospital physician) or confirmed influenza cases admitted to your intensive care unit must be reported according to the following case definition:A patient hospitalized in an intensive care unit who presents with: - a biologically confirmed diagnosis of influenza; - a severe clinical condition with no other identified etiology, whose clinical presentation and medical history suggest a diagnosis of influenza even if biological confirmation cannot be obtained (probable case).