Real-time comparative monitoring of the A/H1N1 pandemic in France.

The clinical burden of the A/H1NI influenza pandemic in the general population is comparable to those of previous seasonal influenza epidemics in terms of total numbers of clinical cases. It is higher in young, and virtually nil in older adults. These assertions can be made safely because of long-established clinical influenza surveillance systems. However, what characterizes this pandemic is that it may kill young patients without known risk factors. Surveillance systems dedicated to the most severely ill patients admitted to intensive care units have been implemented only recently. The present experience strongly supports the view that they should be made perennial.