10 December 2025 Situation at a glance Seasonal influenza (‘the flu’) is an acute respiratory infection caused by influenza viruses that circulate globally and year-round. It can cause illness ranging from mild to severe , sometimes resulting in hospitalization or death. Seasonal influenza activity has increased globally in recent months, with an increased proportion of seasonal influenza A(H3N2) viruses being detected. This rise coincides with the onset of winter in the northern hemisphere and an increase in acute respiratory infections caused by influenza and other respiratory viruses typically observed at this time of year. Although global activity remains within expected seasonal ranges , early increases and higher activity than typical at this time of year have been observed in some regions. Seasonal influenza viruses, including A(H3N2) viruses, continually evolve over time. Since August 2025, there has been a rapid increase of A(H3N2) J.2...
Media Monitoring for Signals about Emerging Threats