Alale et al.
Tick-borne viruses in Finland: public health risks, interventions and research insights. Vet Med Sci. 2025;11:e70638
A recently published review by Alale et al. provides an updated synthesis of trends in tick-borne encephalitis (TBE) epidemiology, surveillance, and public health interventions in Finland.
TBE was first identified in Finland in the late 1950s, when the virus was isolated from Ixodes ricinus ticks in the southwest archipelago near Kumlinge in the Åland Islands, leading to the local designation “Kumlinge virus.” Human TBE cases were first recognised in the 1960s, although most occurred sporadically and public awareness remained low. While TBE diagnostics have been available in Finland since at least the late 1970s, limited diagnostic capacity likely contributed to underreporting and misclassification during earlier decades.
Despite historically low case numbers, Finnish public health authorities initiated early monitoring efforts, initially focused on the Åland Islands. Systematic, nationwide TBE surveillance began in 1995, followed by enhanced surveillance protocols in 2007 to improve case detection, geographic mapping, and trend analysis.
In response to rising incidence, targeted vaccination programmes were implemented in high-risk regions, beginning with the Åland Islands in 2006, where high vaccination coverage has since been achieved (see Snapshot Week 44/2025). Finland’s main tick vectors are I. ricinus and I. persulcatus, carrying the European and Siberian TBE virus subtypes, respectively. Over the past two decades, I. persulcatus has expanded westward, contributing to changes in geographic risk.
From 1995 to 2024, TBE incidence increased substantially. Between 2020 and 2024 alone, national incidence rose from 1.65 to 3.57 cases per 100,000 population. While some regions maintained low case numbers, substantial increases were reported in Southwest Finland, the City of Helsinki, West Uusimaa, and North Karelia. The highest incidence during this period occurred in Kustavi, reaching 71.3 cases per 100,000 population.
Compared with other TBE-endemic countries, Finland’s vaccination coverage remains suboptimal. This underscores the need for strengthened public awareness, improved risk communication, and regionally tailored prevention strategies.