What will happen if a tick bites after vaccination against tick-borne encephalitis? - briefly
Vaccination against tick‑borne encephalitis generates strong neutralising antibodies, making infection after a bite highly unlikely. If infection does occur, symptoms are usually mild and the chance of severe neurological disease is markedly reduced.
What will happen if a tick bites after vaccination against tick-borne encephalitis? - in detail
If a tick attaches after the administration of the tick‑borne encephalitis (TBE) vaccine, the immune system is already primed to recognize the virus. The vaccine induces the production of neutralising antibodies that circulate in the bloodstream. These antibodies bind to viral particles introduced by the tick, preventing the virus from entering host cells and halting replication.
The typical outcome is one of the following:
- No infection develops; the virus is neutralised before establishing a foothold.
- A subclinical infection occurs; viral replication is limited, symptoms are mild or absent, and the immune response clears the pathogen rapidly.
- Mild, self‑limiting flu‑like illness may appear; the presence of antibodies reduces severity and duration compared with an unvaccinated individual.
Complete protection is not guaranteed. Factors influencing the residual risk include:
- Time elapsed since the last vaccine dose – immunity wanes over months; booster doses restore optimal antibody titres.
- Individual variation in immune response – some persons generate lower antibody levels despite full vaccination.
- Viral load transmitted by the tick – a very high inoculum can overwhelm existing antibodies, increasing the chance of symptomatic disease.
In cases where infection does develop despite vaccination, the clinical course is usually milder. Hospitalisation and severe neurological complications, such as meningitis or encephalitis, are rare among vaccinated patients. Diagnostic testing (serology or PCR) can confirm infection, and supportive care is the mainstay of treatment; specific antiviral therapy for TBE is not available.
Monitoring of post‑exposure symptoms remains advisable. Prompt medical evaluation is recommended if fever, headache, neck stiffness, or neurological signs appear within two weeks of the bite. Early detection allows appropriate management and documentation of vaccine breakthrough cases, contributing to surveillance and future vaccine optimisation.