TBE infections in Finland set to break records, experts warn

Finland is on track to record a new high in tick-borne encephalitis (TBE) infections this year, with 74 cases already reported by mid-June, according to public broadcaster Yle. Last year saw a total of 240 cases.

Experts attribute the rise to an unusually high number of ticks, with the citizen science platform Punkkilive.fi logging 119,000 tick sightings so far this month—nearly matching the 138,000 reported in all of 2025.

Elisa Kortela, an infectious disease specialist at Helsinki University Hospital (HUS), said the early-season surge suggests 2026 will surpass last year’s record. Lotta Simola, an infectious disease specialist at Oulu University Hospital (OYS), noted that TBE cases have been rising in Northern Ostrobothnia since summer 2023, with 20 cases already recorded this year—exceeding the region’s typical annual total of 15–20. A decade ago, the region reported no cases at all.

Coastal and archipelago areas, including Åland, Turku, Helsinki, Oulu, as well as parts of North Savo and North Karelia, are considered high-risk zones. Only about one-third of TBE patients develop symptoms such as fever, headache, or general malaise. Of those, roughly one-third progress to severe encephalitis, which can cause confusion, paralysis, seizures, or loss of consciousness—sometimes requiring intensive care or proving fatal.

Finland has recorded a TBE mortality rate of around 2%, though the actual figure may be lower due to undiagnosed mild cases. Last year, 17% of HUS’s TBE patients required intensive care. There is no cure for TBE; only symptoms can be treated.

Experts strongly recommend vaccination, which offers 97–98% protection. Three doses are required for lasting immunity. The disease can transmit within minutes of a tick bite, unlike Lyme borreliosis, which typically requires 12–24 hours of attachment.

Lyme borreliosis, another tick-borne illness, is more common, with 2,000–2,700 confirmed cases annually. Early tick removal is critical for prevention.