Second five-year follow-up after a booster vaccination against tick-borne encephalitis following different primary vaccination schedules demonstrates at least 10 years antibody persistence

Vaccine. 2019 Jul 26;37(32):4623-4629. doi: 10.1016/j.vaccine.2017.12.081. Epub 2018 Feb 1.


Background: Tick borne encephalitis (TBE) endemic zones are expanding. We previously evaluated long term persistence of antibody 5 years after the first booster immunization following different primary immunization schedules with the polygeline-free inactivated TBE vaccine (TBEvac) in adults and adolescents. Here, we report anti-TBE virus (TBEV) antibody persistence from 6 to 10 years post-booster administration.

Methods: This was a phase IV, open-label, single-center, second extension study (NCT01562444), conducted in Czechia. Healthy adults and adolescents ≥12 years who had received 3 different primary vaccination schedules (rapid, conventional and accelerated conventional) in the parent study and a booster dose before (12-18 months post-primary series completion) or at the beginning (3 years post-primary series completion) of the first extension study were screened and enrolled in this study. Blood samples were collected yearly and anti-TBEV antibody response was evaluated by neutralizing test (NT) antibody assays. Analysis was performed overall and per age strata: 15-49 years, ≥50 years, and ≥60 years.

Results: Of 206 screened individuals, 191 completed the study. Overall, 90-100% of participants in the all-screened set and ≥97% in the per-protocol set had the clinically meaningful threshold of protection (NT titers ≥10) across all timepoints, regardless of the primary vaccination schedule. Overall, antibody geometric mean titers (GMTs) varied from 134 to 343 in the all-screened set. Older age groups showed overall lower GMTs, although GMTs remained higher than NT titers ≥10 up to year 10 in all groups.

Conclusion: This study showed long-term persistence of anti-TBEV NT antibodies for up to 10 years after the first booster dose of TBEvac in all age groups, regardless of the primary vaccination schedule.

Keywords: Adults; Booster; Encepur; Long-term persistence; Tick-borne encephalitis.

Publication types

  • Clinical Trial, Phase IV
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Neutralizing / blood
  • Antibodies, Viral / blood*
  • Child
  • Czech Republic
  • Encephalitis Viruses, Tick-Borne / immunology*
  • Encephalitis, Tick-Borne / prevention & control*
  • Female
  • Follow-Up Studies
  • Humans
  • Immunization Schedule*
  • Immunization, Secondary*
  • Male
  • Middle Aged
  • Time Factors
  • Viral Vaccines / administration & dosage
  • Viral Vaccines / immunology*
  • Young Adult


  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Viral Vaccines