Red tbe

Thus, TBEV PCR should be reserved for immunocompromised patients, who have difficulties activating an antibody response [37]. Most cases were also tested for Lyme neuroborreliosis due to a history of tick bite. In contrast to the Norwegian study, in which a few (5%) of the TBE patients also had a positive Bb intrathecal antibody index, none in our cohort did, suggesting that co-infection is not common in Denmark [9]. Nonetheless, LNB is a common infection of the nervous system in Denmark with an incidence of 2.6/100,000 individuals per year [38].The incidence of TBE increased in our study period, except for a decrease in 2020, which was likely due to COVID-19 travel restrictions resulting in fewer imported cases (Fig. 3). We also observed an increase in test rates, although less than the corresponding incidence rates, along with the positivity rates. The test rate increase in 2018–2019, without an accompanying equivalent incidence rate increase, could be due to the establishment of a new risk area in North Zealand in 2019 (Fig. 3) [4, 13]. Altogether, our data suggested that the increase in TBE cases in the study period was real rather than due to increased test activity.In Denmark, TBE vaccination is self-financed. Currently, national guidelines recommend TBE vaccination for people walking on trails in risk areas combined with regular tick bites, or who walk outside trails in forests and scrubs during the transmission season. In this cohort, only one patient was fully vaccinated and one patient partly, whereas an additional 14 individuals were eligible for vaccination according to guidelines (i.e., living or going on vacation, hunting, doing sports (geocaching, running) or working (woodcutter) in an endemic area) [39]. Our data suggest self-perceived risk of TBE infection may be underestimated by people at risk. Increased public awareness due to media attention on TBE in Denmark has led to a raised vaccine demand in the last few years.Strengths and limitationsThe nationwide design with complete long-term follow-up is an important strength of our study. The comparison to matched controls with HSV-1 encephalitis allowed us to contextualize the morbidity and mortality of TBE, while the matched

TBE patients, although this difference was not seen when we only considered TBE cases with encephalitis. From 2015 to 2023, the incidence rate of TBE increased more than the test rate. This indicated a real increase in TBE cases, and was supported by an increasing positivity rate. ReferencesFactsheet about tick-borne encephalitis (TBE) [Internet] (2017) Available from: P, Strle F (2015) Tick-borne encephalitis: a review of epidemiology, clinical characteristics, and management. World J Clin Cases 3(5):430–441Article PubMed PubMed Central Google Scholar Beauté J, Spiteri G, Warns-Petit E, Zeller H (2018) Tick-borne encephalitis in Europe, 2012 to 2016. Euro Surveill 23(45):1800201Article PubMed PubMed Central Google Scholar The_TBE_Book_7th_Edition [Internet]. Available from: Serum Institut. TBE (Tick-borne Encephalitis) [Internet]. Available from: L, Vapalahti O (2008) Tick-borne encephalitis. Lancet 371(9627):1861–1871Article PubMed Google Scholar Nygren TM, Pilic A, Böhmer MM, Wagner-Wiening C, Wichmann O, Hellenbrand W (2023) Recovery and sequelae in 523 adults and children with tick-borne encephalitis in Germany. Infection 51(5):1503–1511Article PubMed PubMed Central Google Scholar Kaiser R (2008) Tick-borne encephalitis. Infect Dis Clin North Am 22(3):561–75Article PubMed Google Scholar Skudal H, Lorentzen ÅR, Stenstad T, Quist-Paulsen E, Egeland J, Fevang B et al (2024) Clinical characteristics and factors affecting disease severity in hospitalized tick-borne encephalitis patients in Norway from 2018 to 2022. Eur J Clin Microbiol Infect Dis. PubMed PubMed Central Google Scholar Riccardi N, Antonello RM, Luzzati R, Zajkowska J, Di Bella S, Giacobbe DR (2019) Tick-borne encephalitis in Europe: a brief update on epidemiology, diagnosis, prevention, and treatment. Eur J Intern Med 62:1–6Article PubMed Google Scholar Jore S, Viljugrein H, Hjertqvist M, Dub T, Mäkelä H (2023) Outdoor recreation, tick borne encephalitis incidence and seasonality in Finland, Norway and Sweden during the COVID-19 pandemic (2020/2021). Infect Ecol Epidemiol 13(1):2281055PubMed PubMed Central Google Scholar Tick-borne encephalitis Annual Epidemiological Report 2022Statens Serum Institut. TBE - opgørelse over sygdomsforekomst 2020–2023 [Internet]. Available from: mange bestillinger af vaccinationer mod TBE-virus fra flåter [Internet]. Available from: J, Larsen L, Brandt CT, Wiese L, Hansen BR, Andersen CØ et al (2021) Existing data sources for clinical epidemiology: The Danish Study Group of Infections of the Brain Database (DASGIB). Clin

At Statens Serum Institut (SSI). SSI is responsible for monitoring epidemic diseases and providing risk estimations. The increase in TBE cases and new geographical risk areas led to public concern and an unprecedented vaccine demand, and in June 2023, SSI reported having delivered a year’s normal consumption of vaccines within a few weeks [14].The aim of this study was to make a first-time description of the disease course in adult patients hospitalized with TBE in Denmark and determine the yearly incidence and test activity of TBE from 2015 to 2023. This description includes clinical characteristics, objective findings, diagnostic workup, and outcome in terms of sequelae. Outcome was compared to a matched cohort of patients hospitalized with herpes simplex virus type 1 (HSV-1) encephalitis to contextualize the course of TBE.Materials and methodsStudy designWe performed a nationwide prospective cohort study of all adults hospitalized with TBE at departments of infectious diseases in Denmark between 1st of January 2015 and 31st of December 2023.SettingIn December 2023, the total population of Denmark numbered 5.9 million people. In Denmark, healthcare is tax-financed and provided to all residents free of charge. A unique ten-digit personal identification number is assigned to all Danish residents at birth or upon immigration and can be used for linkage of all healthcare information at an individual level.Data sourcesThe Danish Study Group of Infections of the Brain (DASGIB) is a nationwide, population-based, prospective cohort study enrolling all patients ≥ 18 years with a CNS infection managed by departments of infectious diseases in Denmark since 2015 [15]. We used the DASGIB database to identify all adults hospitalized with TBE in the inclusion period. Additionally, a cohort of matched controls with HSV-1 encephalitis was identified. Subjects were matched 1:1 on sex and age ± 5 years. One HSV-1 patient was used as a control for two different TBE patients due to lacking matches.TBE diagnostics (polymerase chain reaction (PCR) and serology) are centralized at SSI. TBEV-IgM and –IgG antibodies in serum and/or cerebrospinal fluid (CSF) were measured using the Serion FSME/TBE Virus ELISA (Serion Diagnostics, Germany) following instructions of the manufacturer. TBEV-RNA in serum and/or