An epidemic curve standard display. Weekly national incidence rates of ILI data (blue dashed line) were obtained from the French Sentinelles Network. ILI was defined as: sudden fever > 39°C (102°F) with myalgia and respiratory signs. Weekly national proportions of confirmed influenza positive samples (virological data, red bar plot) data were downloaded from WHO-FluNet  (data provided by the French National Reference Center for flu, cell culture or PCR test, all influenza virus combined), for mainland France. The grey bar plot at the bottom of the graph corresponds to the number of virological samples analyzed per week.