Vaccines against tick-borne encephalitis (TBE) are effective in preventing TBE. Regular boosters are recommended following basic immunisation. Reports of breakthrough infections are very rare. However, encephalitis or meningoencephalitis with evidence of acute TBE infection can occur in people who have been vaccinated against TBE. The causes (e.g. incomplete vaccine cycle or breakthrough infection due to another cause) must be clarified in such cases.
Encephalitis/meningoencephalitis after vaccination against tick-borne encephalitis (TBE)
Incident data |
Description |
|---|---|
Case: 2022 Age: 48 years Sex: Male Medicinal product: TBE vaccination Active substance: Inactivated TBE virus Indication: Booster according to the Swiss vaccination plan ADR: Encephalitis Outcome: Unknown |
Case of encephalitis in a 48-year-old male, 10 days after a TBE booster – administered 12 years after basic immunisation. The patient was admitted to hospital as an emergency with aphasia, fever and headache and subsequently treated in hospital for encephalitis for 8 days. Lab tests confirmed the diagnosis; however, a viral or bacterial pathogen could not be found. At the time of the report, the outcome of the encephalitis was unknown. |
Case: 2022 Age: 15 years Sex: Male Medicinal product: TBE vaccination Active substance: Inactivated TBE virus Indication: Immunisation ADR: Viral TBE, vaccination failure Outcome: Recovering |
Case of viral TBE in a 15-year-old male, 7 years after the last TBE vaccination. According to the patient's history, he had spent time abroad, where he had had numerous tick bites. Due to his poor general condition, with fever of up to 40ºC and frontal headaches, the patient was hospitalised with suspected viral meningitis. However, given a lack of evidence of microbial growth, the patient was tested and found positive for TBE IgM and IgG. A diagnosis of TBE in the context of breakthrough infection was therefore made. The outcome at the time of the report was “recovering”. |
Case: 2022 Age: 59 years Sex: Female Medicinal product: TBE vaccination (precise vaccine unknown) Active substances: Inactivated TBE virus Indication: Active immunisation ADR: Encephalomyelitis Outcome: Unknown |
The 59-year-old female patient experienced symmetrical proximal muscle weakness in her upper and lower extremities one month after TBE vaccination (precise vaccine unknown). The treating neurologist suspected encephalomyelitis following TBE vaccination. At the time of the report, it was not known whether the patient had recovered from the ADR or whether a pathogen that caused the encephalomyelitis had been detected. |
Summary and recommendation
When encephalitis or meningoencephalitis with evidence of acute TBE infection occurs in individuals who have been vaccinated against TBE, an incomplete vaccine cycle or breakthrough infection due to another cause can usually be assumed.
It is possible that full vaccine protection may not develop following incomplete immunisation. In addition – as with other vaccines – full protection against TBE cannot be guaranteed for all vaccinated individuals (Ref. 1).
To achieve optimum vaccine protection, the vaccination recommendations in the current Swiss vaccination plan must generally be observed (Ref. 2). The product-specific vaccination schedule (basic immunisation and boosters) must be adhered to.
Individual cases of encephalitis or meningoencephalitis with no pathogen detected may occur as an adverse effect of TBE vaccination. These side effects are listed in the information for healthcare professionals for TBE vaccines. In individuals with existing inflammatory CNS diseases, the indication for TBE vaccination must be determined carefully (Ref. 1).
Statutory duty of healthcare professionals to report adverse drug reactions (ADRs)
In Switzerland, healthcare professionals who are authorised to dispense or administer medicinal products are obligated to report severe and/or previously unknown side effects. Reports to Swissmedic can be entered and sent in the Electronic Vigilance Reporting Portal “ElViS” (ElViS login).
Reporting adverse drug reactions
Electronic reports via the ElVis portal