通过疫苗接种后的时间间隔（<5、5-10和10年以上）来评估蜱传脑炎（TBE）疫苗接种的有效性。
回顾,配对病例对照研究参与者:病例-瑞士2006-2020年通过国家强制性疾病报告监测系统报告的所有成人(18-79岁)TBE病例(最终n=1868).来自随机选择的成年人（18-79岁）数据库的对照社区对照参与了2018年瑞士TBE疫苗接种的横断面研究（最终n=4625）。
对于案例和控制，确定接受的TBE疫苗剂量和自上次接种以来的时间.个人被归类为“未接种疫苗”(0剂)，“不完全”(1-2剂)或“完全”(3+剂)。自最后一次接种疫苗以来，已完成疫苗接种的个体按时间进一步分类（<5年，5-10年或10年以上)。使用条件逻辑回归模型来计算每种疫苗接种状态类别的疫苗有效性（VE：100×[1-OR]）。
不完全疫苗接种的VE为76.8％（95％CI69.0％至82.6％）。对于完整的疫苗接种，整体VE为95.0%(95%CI93.5%~96.1%).当最近的剂量小于5年前接受时，VE为91.6％（95％CI为88.4％至94.0％），95.2％（95％CI92.4％至97.0％），当最近的剂量是在5-10年前，和98.5％（95％CI96.8％至99.2％），当最近的剂量是在10年前接受时。
自上次接种疫苗以来，在完全接种疫苗的个体中，VE不会减少超过10年，这支持了完全TBE疫苗接种后保护性反应的寿命。我们的发现支持目前在瑞士使用的10年TBE加强间隔的有效性。
To estimate effectiveness of tickborne encephalitis (
TBE) vaccination by time interval (<5, 5-10 and 10+years) postvaccination.
A retrospective, matched
case-control study PARTICIPANTS: Cases-all adult (age 18-79)
TBE cases in Switzerland reported via the national mandatory disease reporting surveillance system from 2006 to 2020 (final n=1868). Controls-community controls from a database of randomly selected adults (age 18-79) participating in a 2018 cross-sectional study of
TBE vaccination in Switzerland (final n=4625).
For cases and controls, the number of
TBE vaccine doses received and the time since last vaccination were determined. Individuals were classified as being \'unvaccinated\' (0 doses), \'incomplete\' (1-2 doses) or \'complete\' (3+ doses). Individuals with \'complete\' vaccination were further classified by time since the last dose was received (<5 years, 5-10 years or 10+ years). A conditional logistic regression model was used to calculate vaccine effectiveness (VE: 100 × [1-OR]) for each vaccination status category.
VE for incomplete vaccination was 76.8% (95% CI 69.0% to 82.6%). For complete vaccination, overall VE was 95.0% (95% CI 93.5% to 96.1%). When the most recent dose was received <5 years prior VE was 91.6% (95% CI 88.4% to 94.0%), 95.2% (95% CI 92.4% to 97.0%) when the most recent dose was received 5-10 years prior, and 98.5% (95% CI 96.8% to 99.2%) when the most recent dose was received 10+ years prior.
That VE does not decrease among completely vaccinated individuals over 10+ years since last vaccination supports the longevity of the protective response following complete TBE vaccination. Our findings support the effectiveness of 10-year
TBE booster intervals currently used in Switzerland.
