The effect of the TBE vaccination program in the Åland Islands

IF 2.2 Q3 IMMUNOLOGY

Vaccine: X Pub Date : 2025-09-18 DOI:10.1016/j.jvacx.2025.100727

Tove Hoffman , Bo Albinsson , Linda Kolstad , Marika Nordberg , Sirkka Vene , Patrik Ellström , Bengt Rönnberg , Olli Vapalahti , Dag Nyman , Åke Lundkvist

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引用次数: 0

Abstract

Background

The Åland Islands included tick-borne encephalitis (TBE) vaccination in the general vaccination program in 2006.

Aim

Investigate the effect of the vaccination on the number of reported TBE cases and the TBEV IgG seroprevalence in blood donors in the Åland Islands.

Methods

We used reported data on TBE cases (1995–2018) and sera collected from blood donors in 1995 (n = 300) and 2018 (n = 300). Samples were analyzed by a Luminex-based method that can differentiate antibodies induced by a TBE virus (TBEV) infection from those produced after TBE vaccination.

Results

A weak negative trend but no significant relationship between the number of reported TBE cases and year was observed. Of the blood donors, 3.3 % and 7.0 % tested positive for a previous TBEV infection in 1995 and 2018, respectively. There was no significant difference between the blood donor cohorts regarding the number of TBEV-infected and non-infected individuals. The proportion of TBE vaccinated blood donors increased from 2.7 % in 1995 to 81.0 % in 2018. The proportion of previously TBEV-infected unvaccinated blood donors increased from 3.4 % in 1995 to 36.8 % in 2018. The estimated number of unvaccinated individuals decreased 3.8-fold from 1995 to 2018. The rate of TBE cases in the estimated unvaccinated population increased 3.9-fold between the years 1995 and 2018. The risk of being infected by TBEV tended to be higher in 2018, reduced for men, and to increase with age.

Conclusion

The strong increase in seroprevalence of anti-NS1 antibodies and increase of TBE cases in the estimated unvaccinated population seen in this study suggest that the low number of TBE cases in the Åland Islands is explained by the high vaccination coverage, suggesting a positive effect of the free TBE vaccination on public health in the Åland Islands.

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Åland群岛流行性脑炎疫苗接种计划的效果

Åland群岛在2006年将蜱传脑炎（TBE）疫苗接种纳入一般疫苗接种计划。目的调查疫苗接种对Åland群岛献血者报告的TBE病例数和TBEV IgG血清阳性率的影响。方法我们使用1995 - 2018年报道的TBE病例数据和1995年（n = 300）和2018年（n = 300）的献血者血清。采用基于luminex的方法对样品进行分析，该方法可以区分由TBE病毒（TBEV）感染诱导的抗体与接种TBE疫苗后产生的抗体。结果报告病例数与年度呈弱负相关，但无显著相关性。在献血者中，分别有3.3%和7.0%的人在1995年和2018年被检测出感染过乙型肝炎病毒。在献血者队列中，感染和未感染tbev的人数没有显著差异。接种TBE疫苗的献血者比例从1995年的2.7%上升到2018年的81.0%。未接种疫苗的献血者中先前感染乙型脑炎病毒的比例从1995年的3.4%上升到2018年的36.8%。从1995年到2018年，未接种疫苗的人数估计减少了3.8倍。1995年至2018年期间，估计未接种疫苗人群中脑炎病例的发生率增加了3.9倍。2018年被感染的风险趋于较高，男性降低，并随着年龄的增长而增加。结论本研究发现，在未接种疫苗的估计人群中，抗ns1抗体的血清阳性率和TBE病例的增加表明，Åland群岛TBE病例数低可以通过高疫苗接种率来解释，这表明Åland群岛免费接种TBE疫苗对公共卫生有积极影响。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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