From the Valneva Austria GmbH, Vienna, Austria.
Department of Health, Research Institute for Tropical Medicine, Manila, Philippines.
Pediatr Infect Dis J. 2018 Sep;37(9):e233-e240. doi: 10.1097/INF.0000000000002124.
An inactivated Vero cell culture derived Japanese encephalitis virus vaccine (IXIARO) requires a booster dose 1 year after primary schedule for long-term antibody persistence in adults. The aim of this study is to evaluate immunogenicity and safety of a booster dose in children 2 months to <18 years of age.
This is a randomized, controlled open-label study in the Philippines. Three hundred children vaccinated with IXIARO in a previous trial were randomized 1:1 to receive either no booster or a booster 12 months after initiation of the primary series. Neutralizing antibody titers were assessed before and after the booster and up to 3 years after primary series. Safety endpoints included the rate of subjects with solicited adverse events (AEs), unsolicited AEs and serious AEs within 1 month after the booster.
Geometric mean titer declined by 1 year after the primary series, but titers remained above the established protective threshold in 85%-100% of children depending on age group. The booster led to a pronounced increase in geometric mean titer and 100% seroprotection rate in all age groups. The booster was well tolerated, with AE rates lower compared with the primary series. Most AEs were mild.
A booster dose of IXIARO administered 12 months after the primary immunization was well tolerated and highly immunogenic.
一种基于 Vero 细胞培养的灭活日本脑炎病毒疫苗（IXIARO）需要在基础免疫程序完成后 1 年进行加强免疫，以维持成年人的长期抗体持久性。本研究旨在评估加强免疫在 2 个月至<18 岁儿童中的免疫原性和安全性。
这是在菲律宾进行的一项随机、对照、开放性标签研究。300 名在先前试验中接种过 IXIARO 的儿童按照 1:1 的比例随机分组，分别接受加强免疫或不接受加强免疫，加强免疫在基础免疫程序完成后 12 个月进行。在加强免疫前后以及基础免疫程序完成后 3 年内评估中和抗体滴度。安全性终点包括加强免疫后 1 个月内，出现的报告不良事件（AE）、未报告不良事件和严重不良事件的发生率。
基础免疫程序完成 1 年后，几何平均滴度下降，但根据年龄组的不同，仍有 85%-100%的儿童的滴度保持在既定的保护阈值之上。加强免疫导致所有年龄组的几何平均滴度显著升高，且 100%的儿童达到血清保护率。加强免疫的耐受性良好，AE 发生率低于基础免疫程序。大多数 AE 为轻度。
在基础免疫程序完成后 12 个月进行 IXIARO 的加强免疫是安全有效的，具有高度免疫原性。
