Tick-borne encephalitis vaccine effectiveness and barriers to vaccination in Germany

Abstract

Tick-borne encephalitis (TBE) vaccination coverage remains low in Germany. Our case–control study (2018–2020) aimed to examine reasons for low vaccine uptake, vaccine effectiveness (VE), and vaccine breakthrough infections (VBIs). Telephone interviews (581 cases, 975 matched controls) covered vaccinations, vaccination barriers, and confounders identified with directed acyclic graphs. Multivariable logistic regression determined VE as 1—odds ratio with 95% confidence intervals (CI). We additionally calculated VE with the Screening method using routine surveillance and vaccination coverage data. Main vaccination barriers were poor risk perception and fear of adverse events. VE was 96.6% (95% CI 93.7–98.2) for ≥ 3 doses and manufacturer-recommended dosing intervals. Without boosters, VE after ≥ 3 doses at ≤ 10 years was 91.2% (95% CI 82.7–95.6). VE was similar for homologous/heterologous vaccination. Utilising routine surveillance data, VE was comparable (≥ 3 doses: 92.8%). VBIs (n = 17, 2.9% of cases) were older, had more comorbidities and higher severity than unvaccinated cases. However, only few VBIs were diagnostically confirmed; 57% of re-tested vaccinated cases (≥ 1 dose, n = 54) proved false positive. To increase TBE vaccine uptake, communication efforts should address complacency and increase confidence in the vaccines’ safety. The observed duration of high VE may inform decision-makers to consider extending booster intervals to 10 years.

Effectiveness of Tick-borne Encephalitis Vaccines in Children, Latvia, 2018–2020

“…The effectiveness of TBE vaccines in adults has been previously demonstrated in observational studies in Austria, Germany, Latvia and Switzerland. [22][23][24][25] The studies in Austria, Germany and Latvia also included estimates of >92% TBE VE against TBE in children, but this is the first study to provide VE estimates against a range of TBEV infection public health outcomes. [22][23][24] During this study, 2 pediatric TBE vaccines were used in Latvia, and results from our population survey indicate that FSME-IMMUN Junior was used more frequently than Encepur Pediatric/Adult in children 1-15 years-of-age.…”

“…[22][23][24][25] The studies in Austria, Germany and Latvia also included estimates of >92% TBE VE against TBE in children, but this is the first study to provide VE estimates against a range of TBEV infection public health outcomes. [22][23][24] During this study, 2 pediatric TBE vaccines were used in Latvia, and results from our population survey indicate that FSME-IMMUN Junior was used more frequently than Encepur Pediatric/Adult in children 1-15 years-of-age. There were insufficient data to compare VE for the 2 pediatric TBE vaccines; however, we were able to show that FSME-IMMUN Junior was highly effective in preventing medically attended TBEV infection, hospitalization with a TBEV infection and TBE in children 1-15 years-of-age.…”

“…[22][23][24][25] Three of these studies included age-stratified VE estimates with an age group for children and, although VE estimates were lower in children, VE estimates were high (>92%) across all age groups. [22][23][24] Importantly, these studies with VE estimates stratified by children only reported VE against TBE. None of the previous studies reported VE estimates for children against a range of TBEV infection public health outcomes (medically attended TBEV infection, hospitalization, etc.).…”

“…21 Studies have reported a real-world TBE vaccine effectiveness (VE) of ≥95% against TBEV infection and TBE following receipt of the 3-dose primary series and following receipt of 1 or more boosters. [22][23][24][25] Three of these studies included age-stratified VE estimates with an age group for children and, although VE estimates were lower in children, VE estimates were high (>92%) across all age groups. [22][23][24] Importantly, these studies with VE estimates stratified by children only reported VE against TBE.…”

Reiseimpfungen – Hinweise und Empfehlungen

“…Das Schnellimpfschema für Kinder und Erwachsene sollte nur dann zur Anwendung kommen, wenn das Standardimpfschema zeitlich nicht mehr möglich ist. Ob die Intervalle zur Auffrischimpfung nach erfolgter Grundimmunisierung auf bis zu 10 Jahre verlängert werden können, ist gegenwärtig Gegenstand der wissenschaftlichen Diskussion[50][51][52].▶Tab. 5Das Hepatitis-A-Virus wird fäkal-oral übertragen und ist in vielen Ländern der Welt verbreitet.…”