When should an encephalitis vaccine be administered after a tick bite? - briefly
If the bite happens in an area endemic for tick‑borne encephalitis, the vaccine should be administered promptly, preferably within 72 hours, and followed by the standard two‑dose schedule. Administration later than one week after exposure markedly lowers protective efficacy.
When should an encephalitis vaccine be administered after a tick bite? - in detail
Tick‑borne encephalitis (TBE) is endemic in many forested regions of Europe and Asia. After a bite from an infected Ixodes tick, the decision to vaccinate depends on the victim’s immunisation history, the epidemiological risk of the exposure, and the time elapsed since the bite.
If the individual has never received a TBE vaccine, the first dose should be administered as soon as possible, ideally within 48 hours of the bite. Early administration maximises the chance of inducing protective antibodies before the virus reaches the central nervous system, which typically occurs 7–14 days after infection. A single dose given later than 72 hours does not provide reliable post‑exposure protection and is therefore not recommended.
For persons who have started a primary series but have not completed it, the schedule can be accelerated:
- Day 0: administer the missed dose immediately.
- Day 30–90: give the second dose, regardless of the original interval.
- Month 6–12: deliver the third dose to complete the series.
When a partial series has been completed (at least two doses), a booster can be given at any time after the bite; the booster will raise antibody titres rapidly, offering protection within a few weeks.
Contraindications such as severe allergy to vaccine components, acute febrile illness, or immunosuppression must be evaluated before injection. Pregnant or lactating women may receive the vaccine if the risk of infection is high, because the product is inactivated and poses no known fetal hazard.
In summary, the optimal timing is:
- No prior vaccination – first dose within 48 hours of exposure.
- Incomplete primary series – administer the missed dose immediately, then follow the accelerated schedule.
- At least two doses already received – give a booster as soon as possible.
If more than three days have passed and the person remains unvaccinated, observation for symptoms and prompt diagnostic testing are preferred over delayed vaccination, because the protective effect of a single dose declines sharply after this window. Booster intervals after a completed series are 3–5 years, depending on the vaccine brand and local health‑authority recommendations.