Tick-Borne Encephalitis Among Travelers to Europe Highlights Need for Expanded Vaccination Efforts

Findings presented at IDWeek 2025, which took place from October 19 to October 22, 2025, in Atlanta, GA, underscore the persistent risk of tick-borne encephalitis (TBE) among international travelers and highlight the importance of vaccination for individuals visiting endemic areas in Europe.

TBE, caused by the tick-borne encephalitis virus (TBEV), is a potentially life-threatening flaviviral infection transmitted through the bite of infected Ixodes ticks. The disease primarily affects the central nervous system and may result in severe neurologic complications or death if untreated. 

The geographical distribution of TBE-endemic areas has been mapped for 25 European countries such as Austria, Germany, Switzerland, Sweden, etc. (Figure 1). The local expansions of the endemic areas have gone hand in hand with the total number of cases reported by the surveillance system all over Europe, which in turn is explained by both ecological and behavioral factors, e.g., higher temperatures, increased outdoor recreation, and changing tick habitats.^1-3

From 24 published studies and one public health surveillance report, the researchers identified 39 travel-associated TBE cases (Figure 2). Among these cases, 46.2% were between 40 and 64 years old, and two-thirds (66.7%) were male (Table 1). The median age was 45 years (range, 0.25–75 years). Most patients exhibited systemic (79.5%) and neuromuscular (64.1%) symptoms, with motor and cognitive problems also frequently reported. Of the 33 patients with clinical information, 32 (97%) required hospitalization, with a median stay of 9 days (range, 3–60 days), and one fatality occurred. Notably, travel-associated TBE was linked to trips from the United States, Israel, and several European nations, with Austria, Russia, Sweden, and Switzerland being the most common destinations.

The clinical burden aligns with previous reports, which described TBE as one of the most serious tick-borne pathogens in Europe and a frequent cause of long-term neurologic sequelae, including paralysis, cognitive impairment, and fatigue syndromes.² That almost all travelers whose cases were reported had to be hospitalized indicates the seriousness of the infections brought from abroad and thus the necessity of more efficient prevention measures, among which vaccination should be included.

Although the effectiveness of TBE vaccines is extensively documented, the coverage of the vaccines among travelers is still quite sporadic. Scientists found out that there are TBE vaccination advisories in 32 countries. However, only 7 countries, including Austria, Estonia, and Latvia, recommend immunization for everyone (residents and travelers), whereas 25 countries limit their guidance to travelers entering endemic areas (Figure 3). Such disparities in health policies may expose both travelers and expatriates to pathogens, especially those visiting areas where the spread of the disease is increasing.

The European Centre for Disease Prevention and Control (ECDC) analyzed the situation of TBE across years 2015 to 2022, stating that out of 22,191 total TBE cases, 376 (1.7%) were travel-associated TBE. Although the percentage is low, experts often point out that such cases represent preventable infections in individuals who might have benefitted from pre-travel consultation and immunization. As climate and vector dynamics shift, the geographic spread of TBE-endemic zones continues to increase, making risk assessment more complex.^2,3

Authors of the IDWeek study stressed that enhanced efforts are needed to vaccinate travelers to TBE-endemic areas in Europe. Many of the cases identified occurred in individuals unaware of the risk or without prior vaccination. In addition to traveler education, experts recommend standardizing vaccine recommendations across European Union member states and ensuring that clinicians routinely discuss TBE risk during pre-travel consultations, particularly for those engaging in outdoor or rural activities.

Pharmacists are instrumental in preventing TBE by identifying and advising at-risk travelers with the right information about the availability of vaccines like FSME-IMMUN and Encepur. Pharmacists may also support the practice of using repellents and the prompt removal of ticks as ways to protect against ticks. Since most travel-related cases are associated with severe disease and hospitalization, pharmacists should encourage at-risk travelers to receive vaccination at least 2 weeks before departure to ensure adequate protection.

As the incidence and geographic spread of TBE continue to rise, particularly in central and northern Europe, these findings highlight a growing need for consistent, proactive vaccination policies and greater public awareness. Continued surveillance and coordinated public health communication are essential to reduce preventable travel-associated infections and ensure safe travel within Europe’s expanding TBE-endemic regions.

REFERENCES

1. Srinivasan R, Angulo F, Duench S, Davidson A, Kelly P, Riddle M, Halsby K, Pilz A, et al. P-180: Tick-borne Encephalitis (TBE) in International Travelers and TBE Vaccine Recommendations for Travelers to Europe Study Presented: IDWeek 2025; October 21, 2025; Atlanta, Georgia. Accessed November 3, 2025 via IDWeek’s online conference platform.

2. Steffen R. Epidemiology of tick-borne encephalitis (TBE) in international travellers to Western/Central Europe and conclusions on vaccination recommendations. J Travel Med. 2016;23(4):taw018. Published 2016 Apr 17. doi:10.1093/jtm/taw018

3. Chrdle A, Chmelík V, Růžek D. Tick-borne encephalitis: What travelers should know when visiting an endemic country. Hum Vaccin Immunother. 2016;12(10):2694-2699. doi:10.1080/21645515.2016.1218098