BACKGROUND: Despite the availability of vaccination, TBE (tick-borne encephalitis) remains a global public health problem. Therefore, the aim of our study was to assess the long-term efficacy of vaccinations against tick-borne encephalitis using vaccines available on the European market.
METHODS: The analysis was conducted on the results of a systematic review conducted in accordance with the Cochrane Handbook for Systematic Reviews of Interventions. The search was performed in three databases, namely Medline (via PubMed), EMBASE (via Ovid), and the Cochrane Library database. The authors followed the PRISMA method and the selection of the articles was performed with two independent researchers.
RESULTS: From a total of 199 citations, 9 studies were included in this review. According to the primary studies identified in the search, the efficacy of available anti-TBE vaccines ranges from 90.1% to 98.9%; however, in individuals above the age of 60, the protection wanes as early as one year after vaccination. Administration of a booster dose 3 years after completion of the basic vaccination schedule significantly extended the period of protection against TBE.
CONCLUSIONS: Anti-TBE vaccines available in Europe have a high level of efficacy. However, the level of protection against TBE is decreasing after vaccination. Therefore, in addition to the conventional schedule, booster vaccines should be administered every 5 years in individuals before the age of 60 and more frequently, e.g. every 3 years, in individuals aged 60 and beyond.

Tick-borne encephalitis (TBE) is an infection caused by the Tick-borne encephalitis virus (TBEv) and it is common in Europe. The virus is predominantly transmitted by ticks, but other non-vectorial modes of transmission are possible. This systematic review synthesises the epidemiological impact of non-vectorial modes of TBEv transmission in Europe. 41 studies were included comprising of 1308 TBE cases. Alimentary (36 studies), handling infected material (3 studies),  blood-borne (1 study), solid organ transplant (1 study) were identified as potential routes of TBEv transmission; however, no evidence of vertical transmission from mother to offspring was reported (2 studies). Consumption of unpasteurised milk/milk products was the most common vehicle of transmission and significantly increased the risk of TBE by three-fold (pooled RR 3.05, 95% CI 1.53 to 6.11; 4 studies). This review also confirms handling infected material, blood-borne and solid organ transplant as potential routes of TBEv transmission. It is important to tracing back to find the vehicle of the viral infection and to promote vaccination as it remains a mainstay for the prevention of TBE.

Tick-borne encephalitis virus (TBEV), which causes central nervous system infections, is a major health problem in Europe and Asia. This virus is transmitted mainly via the bite of a tick. However, an infection may also occur as a result of consuming raw milk. In 2018, a total of 3 092 cases of tick-borne encephalitis (TBE) were reported in EU countries. In recent years, TBE has emerged in previously unaffected regions; thus, new endemic areas have been identified. Most cases of TBE occur in spring and autumn, which correlates with increased tick activity. TBE is found in all age groups, including infants. The clinical presentation of TBE varies, but the severity of the infection and risk of complications increase with age. Post-encephalitic syndrome, which affects up to 50% of infected individuals, significantly reduces quality of life. Currently, there is no effective treatment for TBE, and supportive management is used in the acute phase of the disease. Therefore, anti-TBE immunization and the avoidance of tick bites are of key importance in preventing this infection.

Tick-borne encephalitis (TBE) is increasing in Europe. We aimed to evaluate the immunogenicity and safety of TBE-vaccination.
This systematic review was registered at PROSPERO (#CRD42020155737) and conducted in accordance with PRISMA guidelines. We searched CINAHL, Cochrane, Embase, PubMed, and Scopus using specific terms. Original articles, case reports and research abstracts in English, French, German and Italian were included for screening and extracting (JER; PS).
Of a total of 2464 records, 49 original research publications were evaluated for immunogenicity and safety. TBE-vaccines showed adequate immunogenicity, good safety and interchangeability in adults and children with some differences in long-term protection (Seropositivity in 90.6-100% after primary vaccination; 84.9%-99.4% at 5 year follow up). Primary conventional vaccination schedule (days 0, 28, and 300) demonstrated the best immunogenic results (99-100% of seropositivity). Mixed brand primary vaccination presented adequate safety and immunogenicity with some exceptions. After booster follow-ups, accelerated conventional and rapid vaccination schedules were shown to be comparable in terms of immunogenicity and safety. First booster vaccinations five years after primary vaccination were protective in adults aged <50 years, leading to protective antibody levels from at least 5 years up to 10 years after booster vaccination. In older vaccinees, > 50 years, lower protective antibody titers were found. Allergic individuals showed an adequate response and immunosuppressed individuals a diminished response to TBE-vaccination.
The TBE-vaccination is generally safe with rare serious adverse events. Schedules should, if possible, use the same vaccine brand (non-mixed). TBE-vaccines are immunogenic in terms of antibody response but less so when vaccination is started after the age of 50 years. Age at priming is a key factor in the duration of protection.

OBJECTIVE: The incidence of tick-borne encephalitis (TBE) is increasing in many countries. Magnetic resonance imaging (MRI) in the course of TBE is not regularly performed in children. The aim of our study was evaluating MRI-findings of children and adolescents with TBE.
METHODS: Retrospective evaluation of the charts and MRIs of patients who had been treated for TBE in the four participating hospitals in the last twenty years.
RESULTS: 11 patients (5 male; age at TBE 3 weeks-15 9/12 years; mean 104.9 months) were included. MRI (within the first week after admission) revealed symmetric or asymmetric T2-hyperintensities in both thalami in 7/11 patients with additional bilateral lesions in putamen and/or caudate nucleus in 3 patients, and additional cortical lesions in 2 patients. Our youngest patient presented with T2-hyperintensities affecting the whole left cerebral hemisphere including white and grey matter and both cerebellar hemispheres. One patient had a minimal reversible T2-hyperintensity in the splenium of the corpus callosum (RHSCC). 3/11 patients had a normal MRI. 4/11 patients showed complete neurological recovery (2/4 with a normal MRI, RHSCC patient). 6/11 children survived with significant sequelae: hemiparesis (n = 4); cognitive deficits (n = 4); pharmacoresistant epilepsy (n = 2). One patient died of a malignant brain edema.
CONCLUSIONS: A spectrum of MRI findings can be found in children with TBE, often showing involvement of the subcortical deep grey matter structures. In children presenting with a meningoencephalitis and bilateral thalamic involvement TBE should be included in the differential diagnosis.

Tick-borne encephalitis (TBE) virus, which is usually divided into European, Far Eastern and Siberian subtypes, is a serious public health problem in several European and Asian countries. Vaccination is the most effective measure to prevent TBE; cross-subtype protection elicited by the TBE vaccines is biologically plausible since all TBE virus subtypes are closely related. This manuscript systematically explores available data on the cross-subtype immunogenicity elicited by the currently available Western vaccines based on the European subtype. Completed immunization course of 3 doses of both Western vaccines determined very high seroconversion/seropositivity rates against both Far Eastern and Siberian subtypes among previously flavivirus-naïve subjects. All but one study found no statistically significant difference in titers of neutralizing antibodies against strains belonging to homologous and heterologous subtypes. Pooled analysis of randomized controlled trials on head-to-head comparison of immunogenicity of Western and Russian TBE vaccines did not reveal differences in seroconversion rates against Far Eastern isolates in either hemagglutination inhibition (risk ratio = 0.98, p = 0.83) or enzyme-linked immunosorbent (risk ratio = 0.95, p = 0.44) assays after 2 vaccine doses. This suggests that, in regions where a heterogeneous TBE virus population circulates, vaccines based on the European subtype may be used alongside vaccines based on the Far Eastern subtype. Studies on the field effectiveness of TBE vaccines and investigation of vaccination failures, especially in countries where different subtypes co-circulate, will further elucidate TBE vaccination-induced cross-subtype protection.

The 16th Meeting of the International Scientific Working Group on Tick-Borne Encephalitis (ISW-TBE) - a group of neurologists, general practitioners, clinicians, travel physicians, virologists, paediatricians, and epidemiologists - was held under the title \"Tick-borne Encephalitis - a Notifiable Disease, a Review after One Year\". With the inclusion of TBE in the list of notifiable diseases in 2012, an important measure was established to continue improving the level of evidence on TBE in Europe to better help guide policies and methods to lower the burden of this disease. The conference agenda was divided into six parts concerning Travel Medicine, Epidemiology & Risk Areas, Poster Session with an Epidemiological Update in Europe, Interactive Debate, Cases, and Social Communication and Recommendations. Important topics regarding current epidemiological investigations, risk areas, mobility, cases, TBE in children, treatment options, vaccination rates, and latest news on vaccination were presented and extensively discussed.