Key Points

• In 2024, the number of reported cases nearly doubled compared to the annual number of cases reported since the disease was added to the list of notifiable diseases in 2021.

• The increase in the proportion of cases without clinical severity in 2024 suggests improved surveillance coverage rather than a sudden rise in incidence.

• A cluster of 11 people was identified in Haute-Savoie in the summer of 2024, in a limited area between Thônes and Annecy, confirming the virus’s long-term establishment in this area.