Acknowledgements We thank all GPs participating to the Sentinelles network. Funding: Santé Publique France. Conflict of interest: None declared. Authors’ contributions: PYB, VC, CP, CS, TB designed the study. PYB, CS, TL analysed the data. CG, CT, TH contributed data on incidence. SB, VE, BL, SVDW characterised viruses. PYB drafted the manuscript. BL, SVDW, DLB contributed to the manuscript. All authors approved the last version. Supplementary Data Supplement Click here for additional data file.