Effectiveness of TBE Vaccination in Latvia in 2018–2020

  • Zavadska, D. (Speaker)
  • Freimane, Z. (Co-author)
  • Karelis, G. (Co-author)
  • Lisa R. Harper (Co-author)
  • Cody Bender (Co-author)
  • Pingping Zhang (Co-author)
  • Frederick Angulo (Co-author)
  • Wilhelm Erber (Co-author)
  • Antra Bormane (Co-author)

Activity: Talk or presentation types › Oral presentation

Description

Tick-borne Encephalitis (TBE), a central nervous system infection by the Tick-borne Encephalitis virus (TBEV), is endemic in Latvia and elsewhere in Europe and Asia. TBE can result in death and other severe consequences. In Latvia, TBE vaccination is strongly recommended, and partially government-reimbursed for children 18 years-of-age, but TBE vaccine effectiveness (VE) for various TBEV infection outcomes has not been estimated.. Rīga Stradinš University conducted nationwide population-based surveillance for TBEV-infected cases in collaboration with the Centre for Disease Prevention and Control, the National Reference Laboratory, and 15 hospitals. Serum and cerebrospinal fluid were tested by ELISA for TBEV-specific IgG and IgM antibodies. After informed consent, TBE vaccination history was collected by interview and medical record review. VE (with 95% confidence interval) was estimated using the screening method utilizing vaccine uptake data from population surveys conducted by IPSOS in 2019 and 2020.. From 2018-2020, surveillance identified 716 TBEV-infected cases, 587 of which according to ECDC case definition were classified as TBE cases. 98% (576) of TBE cases were unvaccinated, but 0.3% (2) were fully-vaccinated (on-schedule receipt of all doses). In the IPSOS general population surveys in 2019-2020 56.5% of general population had received at least 1 or more TBE vaccine doses, 24.2% were fully-vaccinated. VE with ≥ 3 doses against laboratory confirmed TBE with hospitalization was 99.5% (97.8-99.9), against TBE with moderate or severe disease was 99.2% (94.6-99.9) and against TBE with hospitalization >12 days as well 99.2% (94.0-99.9). There were 364 TBE virus-infected and 302 TBE cases prevented by TBE vaccine per year.. For the first time, study of TBE VE against different infection and disease outcomes was performed and both EU registered TBE vaccines have shown a very high effectiveness in Latvia.
Period29 Mar 2023
Event titleRSU International Research Conference 2023: Knowledge for Use in Practice
Event typeConference
OrganiserRīga Stradiņš University
LocationRiga, LatviaShow on map
Degree of RecognitionInternational

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