Influenza season has begun around four weeks earlier than usual in the WHO European Region, but current patterns remain consistent with those seen during the 2022–2023 season. Activity levels vary across countries, with some experiencing early increases in cases while others have yet to see significant rises. Alongside influenza, continued circulation of COVID-19, RSV and other respiratory viruses underscores the need for increased vigilance during the winter period.
WHO monitors respiratory illnesses year-round through its Global Influenza Surveillance and Response System, supported by over 170 laboratories worldwide. Member States intensify reporting from early October, enabling WHO to confirm the start of the flu season and track its progression. As of mid-November 2025, influenza test positivity in primary care stands at 17%, and based on historical patterns, the season is expected to peak at around 50% in late December or early January.
Influenza viruses evolve continuously through small genetic changes, making regular monitoring essential for updating seasonal vaccines. In June 2025, scientists detected increased circulation of new H3N2 and H1N1 strains, although neither has shown signs of increased severity. Despite viral evolution, vaccination remains the most effective protection against severe illness, hospitalization and death. WHO experts stress the importance of receiving the seasonal flu vaccine, particularly for groups at higher risk.
Vaccination also continues to play a critical role in preventing severe COVID-19, with studies showing that vaccines saved an estimated 1.6 million lives in the Region between December 2020 and March 2023. In some countries, RSV vaccines are available for older adults, and eligible individuals are encouraged to take them.
The most severe outcomes from influenza, COVID-19 and RSV affect older adults, pregnant women, individuals with chronic illnesses, immunocompromised people, and young children, especially in the case of RSV. Protecting these groups, along with health workers, remains essential.
WHO/Europe urges the public to take simple preventive measures proven effective during the COVID-19 pandemic. These include getting vaccinated when eligible, staying home when unwell, practicing good hand and respiratory hygiene, improving indoor ventilation, and wearing a mask when experiencing symptoms.
