Severe cases of influenza admitted to intensive care units.

Surveillance of severe influenza cases admitted to pediatric and adult intensive care units in France has been in place since 2009. This regionalized surveillance, led by the French Institute for Public Health Surveillance and its regional units, has highlighted differences in the characteristics and number of severe influenza cases admitted to intensive care depending on the circulating influenza viruses.This surveillance has also identified the groups of people most at risk for influenza with complications, such as pregnant women and obese individuals (BMI > 30). These groups have thus been included in the list, established by the High Council for Public Health, of people with risk factors who are targets for influenza vaccination. This surveillance resumed on November 1, 2012. To date, three severe cases of influenza have been reported to the InVS.