The Institute of Infectious Disease and Vaccine, School of Public Health, Zhejiang Chinese Medical University, Hangzhou, China.
Center for Disease Control and Prevention of Yinzhou District, Ningbo, China.
JMIR Public Health Surveill. 2024 Mar 18;10:e53040. doi: 10.2196/53040.
Live attenuated vaccines may be used to prevent nontargeted diseases such as lower respiratory tract infections (LRTIs) due to their nonspecific effects (NSEs).
We aimed to analyze the NSEs of the Japanese encephalitis vaccine on pediatric LRTIs in children aged 25 months to 35 months.
A retrospective cohort study was conducted by using a population-based electronic health record database in Zhejiang, China. Enrolled participants were children born from January 1, 2017, to December 31, 2017, and who were inoculated with the live-attenuated Japanese encephalitis vaccine (JE-L) or inactivated Japanese encephalitis vaccine (JE-I) as the most recent vaccine at 24 months of age. The study was carried out between January 1, 2019, and December 31, 2019. All inpatient and outpatient hospital visits for LRTIs among children aged 25 months to 35 months were recorded. The Andersen-Gill model was used to assess the NSEs of JE-L against LRTIs in children and compared with those of JE-I as the most recent vaccine.
A total of 810 children born in 2017 were enrolled, of whom 585 received JE-L (JE-L cohort) and 225 received JE-I (JE-I cohort) as their last vaccine. The JE-L cohort showed a reduced risk of LRTIs (adjusted hazard ratio [aHR] 0.537, 95% CI 0.416-0.693), including pneumonia (aHR 0.501, 95% CI 0.393-0.638) and acute bronchitis (aHR 0.525, 95% CI 0.396-0.698) at 25 months to 35 months of age. The NSEs provided by JE-L were especially pronounced in female children (aHR 0.305, 95% CI 0.198-0.469) and children without chronic diseases (aHR 0.553, 95% CI 0.420-0.729), without siblings (aHR 0.361, 95% CI 0.255-0.511), with more than 30 inpatient and outpatient hospital visits prior to 24 months of age (aHR 0.163, 95% CI 0.091-0.290), or with 5 to 10 inpatient and outpatient hospital visits due to infectious diseases prior to 24 months old (aHR 0.058, 95% CI 0.017-0.202).
Compared with JE-I, receiving JE-L as the most recent vaccine was associated with lower risk of inpatient and outpatient hospital visits for LRTIs among children aged 25 months to 35 months. The nature of NSEs induced by JE-L should be considered for policymakers and physicians when recommending JE vaccines to those at high risk of infection from the Japanese encephalitis virus.
减毒活疫苗可能因其非特异性效应（NSE）而用于预防非靶向疾病，如下呼吸道感染（LRTIs）。
我们旨在分析乙型脑炎疫苗对 25 至 35 月龄儿童的 LRTIs 的 NSE。
采用中国浙江基于人群的电子健康记录数据库进行回顾性队列研究。入组的参与者为 2017 年 1 月 1 日至 12 月 31 日出生的儿童，并在 24 个月龄时接种过乙型脑炎减毒活疫苗（JE-L）或乙型脑炎灭活疫苗（JE-I）。研究于 2019 年 1 月 1 日至 12 月 31 日进行。记录了 25 至 35 月龄儿童的所有因 LRTIs 而住院和门诊就诊的情况。采用 Andersen-Gill 模型评估 JE-L 对儿童 LRTIs 的 NSE，并与 JE-I 作为最近一次疫苗进行比较。
共纳入 2017 年出生的 810 名儿童，其中 585 名接种了 JE-L（JE-L 队列），225 名接种了 JE-I（JE-I 队列）作为最近一次疫苗。JE-L 队列的 LRTIs 风险降低（调整后的危险比[aHR]0.537，95%CI 0.416-0.693），包括肺炎（aHR 0.501，95%CI 0.393-0.638）和急性支气管炎（aHR 0.525，95%CI 0.396-0.698）。25 至 35 月龄时，JE-L 提供的 NSE 在女性儿童（aHR 0.305，95%CI 0.198-0.469）和无慢性病儿童（aHR 0.553，95%CI 0.420-0.729）中更为明显，无兄弟姐妹的儿童（aHR 0.361，95%CI 0.255-0.511），24 个月龄前有 30 次以上住院和门诊就诊史的儿童（aHR 0.163，95%CI 0.091-0.290），或 24 个月龄前因传染病有 5 至 10 次住院和门诊就诊史的儿童（aHR 0.058，95%CI 0.017-0.202）。
与 JE-I 相比，JE-L 作为最近一次疫苗接种与 25 至 35 月龄儿童因 LRTIs 而住院和门诊就诊的风险降低相关。在向感染日本脑炎病毒风险较高的人群推荐 JE 疫苗时，应考虑 JE-L 引起的 NSE 的性质。
