TBE vaccination recommended at risk of exposure

With the arrival of spring and milder temperatures, more people are spending leisure time outside again. At the same time, one should not forget the danger from tick bites. In recent years, the FOPH has observed an increase in the annual incidence of TBE. This situation is also observed in several European countries. Vaccination is an excellent way to protect against this disease.

The season in which ticks are particularly active begins in March and lasts until November, depending on the weather [1]. Areas where TBE virus infections have occurred have expanded over the past few years. Since 2019, for example, the whole of Switzerland, with the exception of the cantons of Geneva and Ticino, has been considered a TBE risk area [2]. TBE vaccination is recommended for all adults and children 6 years of age and older who live or temporarily reside in a risk area [3]. In younger children, severe disease is rare. Therefore, the situation in children aged 1-5 years should be assessed individually (approved vaccination is from the age of 1 year) [3]. An analysis of app data showed that tick bites are most common during sports and walking, followed by backyard activities [4] (Fig. 1) .

Vaccination achieves high protective effect

Three doses of vaccine are required for complete basic immunization. Temporary protection is achieved after only two doses of vaccine. The first two doses of vaccine are usually given one month apart. For complete vaccine protection, which ensures vaccine protection for at least ten years with a probability ≥95%, a third vaccination is given 5-12 months (TBE-Immun®) or 9-12 months (Encepur®) after the second vaccine dose, depending on the vaccine [2,5]. Booster vaccinations are recommended at ten-year intervals. An interrupted TBE vaccination should always be continued where the vaccination series was interrupted, that is, by administering only the missing doses with the minimum intervals in each case (2 weeks between doses 1 and 2; 5 months between doses 2 and 3; 10 years before a booster vaccination) [6]. The vaccine against TBE is an inactivated vaccine, which can be used concurrently with covid-19 vaccines [7]. The cost of TBE vaccination is covered by mandatory health insurance or reimbursed by the employer in the case of occupational exposure. Vaccinations are generally well tolerated; local reactions at the injection site with temporary pain, redness and swelling may occur. In terms of systemic reactions, general malaise, flu-like symptoms, and fever are most commonly observed, especially after the first vaccination.

TBE can have serious consequences

Tick-borne diseases are on the rise as ticks spread due to global warming and more people spend their leisure time in high-risk areas. Early summer meningoencephalitis (TBE) is an acute inflammation of the brain, meninges and spinal cord caused by a virus of the same name. TBE is often severe and leaves more than one-third of sufferers with permanent neurological damage. So far, no causal therapy exists for TBE.

TBE viruses are mainly transmitted by ticks (in Western Europe Ixodes ricinus and in Eastern Europe, Russia and Asia I. persulcatus). Not every tick bite transmits the TBE virus and not every infected person develops symptoms. Men fall ill about twice as often as women. In particular, people over 60 years of age and patients under immunosuppression have a higher risk of an unfavorable course.

Children are among the risk group for tick bites

While very high TBE case numbers were recorded in 2020, those of 2021 were within the range of fluctuations observed annually [1]. Regularly updated maps providing information on the regional risk of a tick bite or TBE infection are published by the FOPH in collaboration with the Federal Office of Topography [1,8]. Whether or what effect the extension of the vaccination recommendation has on TBE vaccination rates will be evaluated in future survey waves. Since children often spend time where ticks can be found, they are particularly at risk and belong to the risk group. As data from the Swiss National Vaccination Coverage Survey (SNVCS) show, since 2014-2016, the national vaccination coverage rate for 8-year-olds has increased significantly, reaching 32% for three doses during the 2017-2019 survey period [1,9]. For 16-year-olds, on the other hand, it has barely increased since 2014-2016 and stands at 41%. In cantons with endemic areas, the median vaccination rate for three doses was 37% among 8-year-olds and 47% among 16-year-olds.

App as additional protection and source of information

The frequency of tick bites has additionally been recorded via the BAG-subsidized “Tick” app since 2015 and will be presented in a report for the first time in 2021. The free interactive app from the Zurich University of Applied Sciences (ZHAW) has been developed into a comprehensive prevention and data tool [10]. The app consists of a warning and an information part. She educates about the proper behavior in the event of a tick bite and how to protect yourself from ticks outside. The warning function also provides information about the current tick hazard potential in the field. The dynamic warning shows the user the risk of ticks during the excursion using a five-point scale. After a tick bite, the user enters this in the integrated tick diary. The app automatically reminds the user of the tick bite after 5, 10 and 28 days and displays descriptions of possible symptoms. The focus is on Lyme disease, for which, in contrast to TBE, there is currently no vaccination. The app is free to download for Android and iOS devices on Google Play and Appstore.

Literature:

Federal Office of Public Health: FOPH Bulletin Week 16/2021.
Federal Office of Public Health, Federal Commission on Immunization. Early summer meningoencephalitis (TBE): expansion of risk areas. FOPH Bulletin 2019; no. 6: 1: 12-14.
Federal Office of Public Health: Swiss Vaccination Plan 2021. Federal Office of Public Health and Federal Commission for Vaccination Matters, as of January 2021
Zurich University of Applied Sciences: free interactive app “Tick” www.zhaw.ch/de/lsfm/dienstleistung/umwelt-und-natuerliche-ressourcen/zecken/app-zecke (last accessed 17.02.2022)
Swissmedicinfo: Medicinal Product Information, www.swissmedicinfo.ch (last accessed Feb. 17, 2022).
Pharmasuisse, Vaccinations, https://www.pharmasuisse.org (last accessed Feb. 17, 2022).
Infektionsschutz.de, www.infektionsschutz.de/coronavirus/schutzimpfung/impfung-gegen-covid-19-zeitgleich-mit-anderen-impfungen (last accessed Feb. 17, 2022).
Swisstopo, https://map.geo.admin.ch (last accessed Feb. 17, 2022).
Swiss National Vaccination Coverage Survey 2005-2019
Zurich University of Applied Sciences, www.zhaw.ch/de/medien/medienmitteilungen/detailansicht-medienmitteilung/event-news/zecken-stechen-kinder-vor-allem-an-kopf-und-hals (last accessed 17.02.2022)
S1 Guideline, AWMF Register Number: 030/03, www.awmf.org/uploads/tx_szleitlinien/030-035l_S1_Fruehsommer_Meningoenzephalitis_FSME_2020-02.pdf (last accessed Feb. 17, 2022).