Sweden Faces Record High Tick-Borne Encephalitis Cases in 2026 with Urgent Vaccination Calls

Sweden is experiencing an unprecedented surge in Tick-Borne Encephalitis (TBE) cases in 2026, with 448 infections reported by September 14, marking the highest number ever recorded for this period. This surpasses the prior record of 392 cases set in 2023, according to the Public Health Agency of Sweden (Folkhälsomyndigheten).

TBE is a serious viral infection transmitted by ticks, which can cause severe health complications including inflammation of the brain and meninges, paralysis, and in some cases, death. Approximately one-third of those infected suffer severe illness, often necessitating hospitalization. Typically, between 250 and 350 people are hospitalized annually due to TBE in Sweden.

The factors behind this record increase remain unclear but are believed to involve a combination of environmental elements such as elevated tick and host animal populations, including deer and rodents, and weather conditions favorable for tick activity. Over the past decade, reported TBE infections have risen annually by about 6%.

In response, the Public Health Agency introduced national vaccination recommendations in May 2026 for the first time. Vaccination is advised for individuals aged three and above who are at risk of tick exposure in moderate to high prevalence areas of Sweden. As immunity requires multiple vaccine doses, the agency stresses that vaccinations should not be delayed until spring, emphasizing that ticks remain active into the autumn months.

Older adults are recognized as being at heightened risk for severe disease from TBE, making prevention and vaccination critical. While it is still early to assess the impact of these new immunization guidelines on vaccination rates, the agency remains vigilant in its warning.

This record incidence highlights growing public health concerns about tick-borne diseases in Sweden and underscores the urgent need for preventive measures such as vaccination and tick bite precautions going into the fall season.