Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.
J Travel Med. 2024 Oct 19;31(7). doi: 10.1093/jtm/taad053.
The purpose of this exploratory study was to evaluate different accelerated tick-borne encephalitis (TBE) vaccine schedules for last-minute travellers.
In a single-centre, open-label pilot study, 77 TBE-naïve Belgian soldiers were randomized to one of the following five schedules with FSME-Immun®: group 1 ('classical accelerated' schedule) received one intramuscular (IM) dose at Day 0 and Day 14, group 2 two IM doses at Day 0, group 3 two intradermal (ID) doses at Day 0, group 4 two ID doses at Day 0 and Day 7 and group 5 two ID doses at Day 0 and Day 14. The last dose(s) of the primary vaccination scheme were given after 1 year: IM (1 dose) or ID (2 doses). TBE virus neutralizing antibodies were measured in a plaque reduction neutralization test (PRNT90 and 50) at Days 0, 14, 21, 28, Months 3, 6, 12 and 12+21 days. Seropositivity was defined as neutralizing antibody titres ≥10.
The median age was 19-19.5 years in each group.Median time to seropositivity up to Day 28 was shortest for PRNT90 in ID-group 4 and for PRNT50 in all ID groups. Seroconversion until Day 28 peaked highest for PRNT90 in ID-group 4 (79%) and for PRNT50 in ID-groups 4 and 5 (both 100%). Seropositivity after the last vaccination after 12 months was high in all groups. Previous yellow fever vaccination was reported in 16% and associated with lower geometric mean titres of TBE-specific antibodies at all-time points.The vaccine was generally well tolerated. However, mild to moderate local reactions occurred in 73-100% of ID compared with 0-38% of IM vaccinations, and persistent discolouration was observed in nine ID vaccinated individuals.
The accelerated two-visit ID schedules might offer a better immunological alternative to the recommended classical accelerated IM schedule, but an aluminium-free vaccine would be preferable.
本探索性研究旨在评估针对临时出行者的不同加速 tick-borne encephalitis（TBE）疫苗接种方案。
在一项单中心、开放性试验研究中，77 名 TBE 初治的比利时士兵被随机分为以下五个使用 FSME-Immun®的组别之一：第 1 组（“经典加速”方案）在第 0 天和第 14 天接受 1 次肌内（IM）剂量，第 2 组在第 0 天接受 2 次 IM 剂量，第 3 组在第 0 天接受 2 次皮内（ID）剂量，第 4 组在第 0 天和第 7 天接受 2 次 ID 剂量，第 5 组在第 0 天和第 14 天接受 2 次 ID 剂量。主要疫苗接种方案的最后一剂（1 剂 IM 或 2 剂 ID）在 1 年后给予。在第 0 天、第 14 天、第 21 天、第 28 天、第 3 个月、第 6 个月、第 12 个月和第 12+21 天使用噬斑减少中和试验（PRNT90 和 50）测量 TBE 病毒中和抗体。将中和抗体滴度≥10 定义为血清阳性。
各组的中位年龄为 19-19.5 岁。在第 28 天之前，ID 组 4 的 PRNT90 和所有 ID 组的 PRNT50 达到血清阳性的中位时间最短。ID 组 4 的 PRNT90 （79%）和 ID 组 4 和 5 的 PRNT50（均为 100%）的血清转化率在第 28 天达到峰值最高。所有组在 12 个月后的最后一次接种后均表现出较高的血清阳性率。16%的参与者报告曾接种过黄热病疫苗，这与所有时间点的 TBE 特异性抗体的几何均数滴度较低有关。疫苗通常具有良好的耐受性。然而，与 0-38%的肌内接种相比，ID 接种中发生了 73-100%的轻度至中度局部反应，9 名 ID 接种者出现了持续变色。
加速两剂 ID 方案可能提供了一种优于推荐的经典加速 IM 方案的更好的免疫替代方案，但最好使用不含铝佐剂的疫苗。
