Swedish Tick-Borne Encephalitis Cases Reach Record High, Officials Urge Vaccination

According to the latest data from Sweden's Public Health Agency, 448 cases of tick-borne encephalitis have been confirmed up to September 14, setting an all-time record and exceeding the 2023 figure of 392. Most infected individuals show no symptoms, but 10-30% experience a short flu-like illness, and of those, 20-30% risk a second phase where the virus attacks the brain or meninges; some patients develop severe symptoms immediately.

Caroline Schönning, an investigator at the agency, notes that the rise is likely linked to a combination of tick population growth, the abundance of deer and rodents, and warmer weather extending the tick season. Over the past decade, TBE infections have risen roughly 6% annually. In response, the agency has updated its guidance, urging vaccination for all adults and children over three in the heavily infested southern counties, though it has not yet assessed the uptake. Officials stress that vaccination requires multiple doses and that tick activity will continue well into autumn, so immediate immunisation is advisable for those spending time in high-risk areas.