How long does a vaccine against tick-borne encephalitis remain effective? - briefly
The TBE vaccine confers immunity for roughly three to five years after the full primary course, after which a booster is required. Booster intervals are typically set at three‑year periods for high‑risk individuals and five‑year periods for lower‑risk groups.
How long does a vaccine against tick-borne encephalitis remain effective? - in detail
The protection conferred by the tick‑borne encephalitis (TBE) vaccine persists for several years, but the exact duration depends on the vaccine type, the primary immunisation schedule, age, and individual immune status.
After completing the standard three‑dose primary series (0, 1–3 months, and 5–12 months), seroprotection rates exceed 95 % in healthy adults. Studies show that antibody titres remain above protective thresholds for at least five years in the majority of recipients. Consequently, many health authorities recommend a booster dose at the 5‑year mark to maintain optimal immunity.
Factors influencing the longevity of protection:
- Vaccine formulation: Both FSME‑IMMUN and Encepur demonstrate comparable durability, though some data suggest slightly longer persistence with Encepur in younger adults.
- Age: Individuals over 60 years experience a more rapid decline in antibody levels; a booster at 3–5 years may be advisable.
- Immunocompromised status: Patients with chronic illnesses or on immunosuppressive therapy often require earlier and more frequent boosters, typically every 3 years.
- Geographic exposure: Residents of high‑incidence regions may benefit from an additional booster after 3 years, especially if seasonal exposure is intense.
Booster schedule recommendations:
- Standard adult population – booster at 5 years after the primary series; subsequent boosters every 5 years.
- Adults ≥ 60 years – booster at 3–5 years; thereafter every 5 years, with serological testing to confirm protection.
- Immunosuppressed individuals – booster at 3 years, then every 3–5 years; consider measuring anti‑TBE IgG titres before each booster.
Serological monitoring can identify waning immunity. Protective titres are defined as ≥ 10 IU/mL; values below this threshold indicate the need for an immediate booster regardless of the calendar schedule.
In summary, the vaccine provides robust protection for at least five years in most recipients, with booster intervals adjusted according to age, health status, and exposure risk to ensure sustained immunity.