A new mutated seasonal influenza variant from the UK is spreading rapidly in Sweden, evading the immune system. Authorities warn of a tougher season than usual and urge more people to vaccinate, especially risk groups. Experts discuss how severe the winter could become.
A new type of seasonal influenza, a mutated variant, is spreading rapidly and appears to trick the body's immune system, even in vaccinated individuals or those with prior immunity. The variant, known as K, originates from the UK and has already reached Sweden. Symptoms include fever, cough, and body aches.
In the UK, authorities warn of the worst flu season in ten years. In Sweden, the spread is increasing already now, although January and February are typically peak months. According to the Public Health Agency, this could be due to the British variant, making the season more infectious and tougher than other years.
Epidemiologist Annasara Carnahan at the Public Health Agency says: "More, especially risk groups and those over 65, should vaccinate." She adds: "How strong the season will be, we have to wait and see."
In an Aftonbladet podcast, virologist Niklas Arnberg, general secretary of the Virus and Pandemic Foundation, discusses how bad the flu season in Sweden could become and when the peak will be reached. The podcast, aired on November 14, 2025, includes clips from TV4, BBC, ABC, and Channel 5 News.
SVT News reported on November 22, 2025, about the risk of a more infectious season. Experts emphasize the importance of vaccination to mitigate effects, particularly for the elderly and risk groups.