Zhang Chao, Liu Yan, Luo Xiaofu, Han Liping, Shen Jianyong
Huzhou Center for Disease Control and Prevention, Huzhou, China.
PLoS One. 2025 Jun 16;20(6):e0326257. doi: 10.1371/journal.pone.0326257. eCollection 2025.
Live attenuated Japanese encephalitis vaccine (JEV-L) was included in the Expanded program on immunization on Immunization (EPI) in 2008 and has had a satisfactory effectiveness and safety profile in protecting children from JE virus infection. This study was designed to evaluate the surveillance sensitivity and changes over time of adverse event following immunization (AEFI) reports related to JEV-L based on the national AEFI surveillance system(NAEFISS) data before and after the introduction of vaccine administration law (LAW) from 2014 to2023 in Huzhou City.
AEFI data were collected from NAEFISS from 2014 to 2023 and included age, AEFI and diagnostic categories. AEFI incidence rates are calculated/10,000 vaccine doses and a reporting odds ratio -1.96 standard error (ROR-1.96SE) >1 defined a positive signal between AEFI and vaccine. We categorized the time interval into the pre-LAW period (2014-2019) and post-LAW period (2020-2023) to demonstrate the impact of LAW on the surveillance of AEFI.
The NAEFISS collected 225 AEFI reports after administering 599,223 doses of JEV-L, with a AEFI reported rate of 3.75/10,000 doses. Overall AEFI reported rates increased over time with a drop in 2020 (P < 0.001, χ2 for trend). The reported rate of AEFI in post-LAW period was higher than that in the pre-LAW period (P < 0.001), accounted for increases in fever, local redness and local induration. However, the reported rate of urticaria decreased significantly in post-LAW period(P = 0.043). This study found a positive signal association between JEV-L immunization and fever in the pre- (1.394) and post-LAW period(2.833) and a signal for urticaria in the pre-LAW period (2.098). There were only 2 severe reactions reported: thrombocytopenia and epilepsy.
The implementation of the LAW significantly enhanced the surveillance capacity and sensitivity for AEFIs associated with JEV-L. This study did not find any new/unexpected safety concern in the post-LAW period. Severe reactions remain rare despite the greatly improved sensitivity of surveillance, indicating that the vaccine was comparatively safe. However, continuous epidemiological investigation are needed to systematically assessment the data provided by NAEFISS.
减毒活日本脑炎疫苗（JEV-L）于2008年被纳入扩大免疫规划（EPI），在保护儿童免受日本脑炎病毒感染方面具有令人满意的有效性和安全性。本研究旨在基于湖州市2014年至2023年引入疫苗管理法（LAW）前后的国家预防接种异常反应监测系统（NAEFISS）数据，评估与JEV-L相关的预防接种异常反应（AEFI）报告的监测敏感性及随时间的变化。
收集202014年至2023年NAEFISS中的AEFI数据，包括年龄、AEFI及诊断类别。计算AEFI发病率（每10000剂疫苗），报告比值比-1.96标准误（ROR-1.96SE）>1定义为AEFI与疫苗之间存在阳性信号。我们将时间间隔分为LAW实施前时期（2014-2019年）和LAW实施后时期（2020-2023年），以证明LAW对AEFI监测的影响。
NAEFISS在接种599223剂JEV-L后收集到225份AEFI报告，AEFI报告率为3.75/10000剂。总体AEFI报告率随时间增加，2020年有所下降（P<0.001，趋势χ2检验）。LAW实施后时期的AEFI报告率高于LAW实施前时期（P<0.001），主要表现为发热、局部发红和局部硬结增加。然而，LAW实施后时期荨麻疹的报告率显著下降（P=0.043）。本研究发现JEV-L免疫接种与LAW实施前时期（1.394）和LAW实施后时期（2.833）的发热之间存在阳性信号关联，以及LAW实施前时期荨麻疹的信号（2.098）。仅报告了2例严重反应：血小板减少症和癫痫。
LAW的实施显著提高了与JEV-L相关的AEFI的监测能力和敏感性。本研究在LAW实施后时期未发现任何新的/意外的安全问题。尽管监测敏感性大大提高，但严重反应仍然罕见，表明该疫苗相对安全。然而，需要持续进行流行病学调查以系统评估NAEFISS提供的数据。
