TY - JOUR
T1 - Effectiveness of tick-borne encephalitis vaccination in Latvia, 2018-2020
T2 - an observational study
AU - Zavadska, Dace
AU - Freimane, Zane
AU - Karelis, Guntis
AU - Ermina, Ineta
AU - Harper, Lisa R
AU - Bender, Cody
AU - Zhang, Pingping
AU - Angulo, Frederick J
AU - Erber, Wilhelm
AU - Bormane, Antra
AU - Gutmane, Evija
AU - Litauniece, Zane A
AU - Tihonovs, Jevgenijs
AU - Griskevica, Aija
AU - Madhava, Harish
AU - Jodar, Luis
N1 - Funding Information:
DZ declares a research grant within the Research Collaboration to Rīga Stradinš University (employer) from Pfizer Vaccines. ZF declares editorial support for the manuscript by Pfizer. LRH, CB, PZ, FJA, WE, AG, HM, and LJ are employees of Pfizer Inc. and hold stock and stock options in Pfizer Inc. GK, IE, AB, EG, ZAL, and JT declare that they have no conflicts of interest. Rīga Stradinš University and Pfizer funded this study and were involved in the study design, analysis, interpretation of data, writing of the report, and in the decision to submit the paper for publication.We acknowledge Jennifer Moïsi of Pfizer for her helpful comments and suggestions on the study design and manuscript. We acknowledge Melissa Furtado of Pfizer, for providing medical writing support and editorial assistance funded by Pfizer Inc. for this manuscript. We acknowledge Andreas Pilz of Pfizer and Anja Gilvad of Ipsos for their leadership and assistance with the population surveys. We also acknowledge our collaborators in the National Microbiology Reference Laboratory. Finally, we acknowledge our collaborators at all 15 hospitals in Latvia for their support in identifying and gathering information from all TBEV-infected patients during the study period. The results of the study were presented as a poster at the 33rd European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2023), Copenhagen, Denmark (15‒18 April 2023).
Funding Information:
We acknowledge Jennifer Moïsi of Pfizer for her helpful comments and suggestions on the study design and manuscript. We acknowledge Melissa Furtado of Pfizer , for providing medical writing support and editorial assistance funded by Pfizer Inc. for this manuscript. We acknowledge Andreas Pilz of Pfizer and Anja Gilvad of Ipsos for their leadership and assistance with the population surveys. We also acknowledge our collaborators in the National Microbiology Reference Laboratory. Finally, we acknowledge our collaborators at all 15 hospitals in Latvia for their support in identifying and gathering information from all TBEV-infected patients during the study period. The results of the study were presented as a poster at the 33rd European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2023), Copenhagen, Denmark (15‒18 April 2023).
Funding Information:
DZ declares a research grant within the Research Collaboration to Rīga Stradinš University (employer) from Pfizer Vaccines. ZF declares editorial support for the manuscript by Pfizer. LRH, CB, PZ, FJA, WE, AG, HM, and LJ are employees of Pfizer Inc. and hold stock and stock options in Pfizer Inc. GK, IE, AB, EG, ZAL, and JT declare that they have no conflicts of interest. Rīga Stradinš University and Pfizer funded this study and were involved in the study design, analysis, interpretation of data, writing of the report, and in the decision to submit the paper for publication.
Publisher Copyright:
© 2023 The Author(s)
PY - 2023/11
Y1 - 2023/11
N2 - OBJECTIVES: Tick-borne encephalitis (TBE) is an infection by the tick-borne encephalitis virus (TBEV) that results in symptoms of central nervous system inflammation. TBE is endemic in Latvia and other European countries. TBE vaccines are commonly used in Latvia, but vaccine effectiveness estimates are limited.METHODS: Study staff at Rīga Stradinš University conducted nationwide active surveillance for TBEV infections. Serum and cerebrospinal fluid were ELISA-tested for TBEV-specific IgG and IgM antibodies. Vaccination history was collected by interview and medical record review. Utilising data from surveillance and population surveys, vaccine effectiveness (with 95% confidence intervals) and cases averted were estimated using the screening method.RESULTS: There were 587 laboratory-identified TBE cases from 2018-2020; 98.1% (576/587) were unvaccinated, 1.5% (9/587) were unknown or partially-vaccinated, and 0.3% (2/587) were fully-vaccinated (three-dose primary series and appropriately timed boosters). TBE resulted in the death of 1.7% (10/587) of TBE cases. TBE vaccine history was ascertained from 92.0% (13,247/14,399) people from the general population: 38.6% (5113/13,247) were unvaccinated, 26.3% (3484/13,247) were fully-vaccinated, and 35.1% (4650/13,247) were partially-vaccinated. TBE vaccine effectiveness was 99.5% (98.0-99.9) against TBE, 99.5% (97.9-99.9) against TBE hospitalisation, 99.3% (94.8-99.9) against moderate/severe TBE, and 99.2% (94.4-99.9) against TBE hospitalisation >12 days. From 2018-2020, vaccination averted 906 TBE cases, including 20 deaths.CONCLUSIONS: TBE vaccine was highly effective in preventing TBE, moderate and severe disease, and prolonged hospitalisation. To prevent life-threatening TBE, TBE vaccine uptake and compliance should be increased in Latvia and other European regions where TBE is endemic.
AB - OBJECTIVES: Tick-borne encephalitis (TBE) is an infection by the tick-borne encephalitis virus (TBEV) that results in symptoms of central nervous system inflammation. TBE is endemic in Latvia and other European countries. TBE vaccines are commonly used in Latvia, but vaccine effectiveness estimates are limited.METHODS: Study staff at Rīga Stradinš University conducted nationwide active surveillance for TBEV infections. Serum and cerebrospinal fluid were ELISA-tested for TBEV-specific IgG and IgM antibodies. Vaccination history was collected by interview and medical record review. Utilising data from surveillance and population surveys, vaccine effectiveness (with 95% confidence intervals) and cases averted were estimated using the screening method.RESULTS: There were 587 laboratory-identified TBE cases from 2018-2020; 98.1% (576/587) were unvaccinated, 1.5% (9/587) were unknown or partially-vaccinated, and 0.3% (2/587) were fully-vaccinated (three-dose primary series and appropriately timed boosters). TBE resulted in the death of 1.7% (10/587) of TBE cases. TBE vaccine history was ascertained from 92.0% (13,247/14,399) people from the general population: 38.6% (5113/13,247) were unvaccinated, 26.3% (3484/13,247) were fully-vaccinated, and 35.1% (4650/13,247) were partially-vaccinated. TBE vaccine effectiveness was 99.5% (98.0-99.9) against TBE, 99.5% (97.9-99.9) against TBE hospitalisation, 99.3% (94.8-99.9) against moderate/severe TBE, and 99.2% (94.4-99.9) against TBE hospitalisation >12 days. From 2018-2020, vaccination averted 906 TBE cases, including 20 deaths.CONCLUSIONS: TBE vaccine was highly effective in preventing TBE, moderate and severe disease, and prolonged hospitalisation. To prevent life-threatening TBE, TBE vaccine uptake and compliance should be increased in Latvia and other European regions where TBE is endemic.
UR - https://www-webofscience-com.db.rsu.lv/wos/alldb/full-record/MEDLINE:37422077
UR - http://www.scopus.com/inward/record.url?scp=85166654898&partnerID=8YFLogxK
U2 - 10.1016/j.cmi.2023.06.028
DO - 10.1016/j.cmi.2023.06.028
M3 - Article
C2 - 37422077
SN - 1198-743X
VL - 29
SP - 1443
EP - 1448
JO - Clinical Microbiology and Infection
JF - Clinical Microbiology and Infection
IS - 11
ER -
