Division of Vector-Borne Diseases, United States Centers for Disease Control and Prevention, 3156 Rampart Rd, Fort Collins, CO, USA.
Naval Health Research Center, 140 Sylvester Rd, San Diego, CA, USA.
Vaccine. 2020 Oct 14;38(44):6899-6903. doi: 10.1016/j.vaccine.2020.08.061. Epub 2020 Sep 6.
Japanese encephalitis (JE) virus is an important cause of neurological disease in Asia. JE vaccine is recommended for travelers with higher JE risk itineraries. Inactivated Vero cell culture-derived JE vaccine (JE-VC) is the only JE vaccine currently available in the United States. An inactivated mouse brain-derived JE vaccine (JE-MB) previously was available but production was discontinued. One JE-VC dose administered to adults previously vaccinated with ≥3 doses of JE-MB provides good short-term protection for at least one month, but data on longer-term protection are limited. We evaluated non-inferiority of the JE virus neutralizing antibody response at 12-23 months in JE-MB-vaccinated adults administered one JE-VC dose compared with JE vaccine-naïve adults administered a JE-VC two-dose primary series.
We obtained archived sera from U.S. military personnel and performed a 50% plaque reduction neutralization test for anti-JE virus neutralizing antibodies. We compared the geometric mean titer (GMT) and seroprotection rate at 12-23 months after one JE-VC dose in previously JE-MB-vaccinated personnel and after the second JE-VC dose in previously JE vaccine-naïve personnel. Non-inferiority was concluded if the lower bound of the two-sided 95% confidence interval (CI) of the GMT ratio in previously vaccinated to vaccine-naïve personnel was >1/1.5.
The GMT in previously JE-MB-vaccinated persons was 75 (95% CI 63-90) and in previously JE vaccine-naïve persons was 12 (95% CI 11-14), and seroprotection rates were 94% (235/250) and 54% (135/250), respectively. The ratio of GMTs was 6.3 (95% CI: 5.0-7.7), satisfying the criterion for non-inferiority.
One JE-VC dose in previously JE-MB-vaccinated military personnel provides good protection for at least 1-2 years. The benefits of administration of a single JE-VC dose in previously JE-MB-vaccinated adults include a shorter time to completion of re-vaccination before travel, a decrease in the risk of adverse events, and reduced costs.
日本脑炎 (JE) 病毒是亚洲地区神经系统疾病的重要病因。JE 疫苗推荐用于具有较高 JE 风险行程的旅行者。目前，在美国仅有一种使用 Vero 细胞培养的灭活 JE 疫苗（JE-VC）。以前有使用鼠脑来源的灭活 JE 疫苗（JE-MB），但现已停产。先前已接种 ≥3 剂 JE-MB 的成年人接种一剂 JE-VC 可提供至少一个月的良好短期保护，但关于长期保护的数据有限。我们评估了先前接种过 JE-MB 的成年人接种一剂 JE-VC 与未接种 JE 疫苗的成年人接种 JE-VC 两剂初级系列相比，在 12-23 个月时 JE 病毒中和抗体反应的非劣效性。
我们从美国军人中获得了存档的血清，并进行了抗 JE 病毒中和抗体的 50%蚀斑减少中和试验。我们比较了先前接种过 JE-MB 的人员在接种一剂 JE-VC 后 12-23 个月的几何平均滴度（GMT）和血清保护率，以及先前未接种 JE 疫苗的人员在接种第二剂 JE-VC 后的 GMT。如果先前接种疫苗的人员与未接种疫苗的人员的 GMT 比值的双侧 95%置信区间（CI）下限大于 1/1.5，则认为非劣效性成立。
先前接种过 JE-MB 的人员的 GMT 为 75（95%CI 63-90），而先前未接种 JE 疫苗的人员的 GMT 为 12（95%CI 11-14），血清保护率分别为 94%（235/250）和 54%（135/250）。GMT 比值为 6.3（95%CI：5.0-7.7），满足非劣效性标准。
在先前接种过 JE-MB 的军人中接种一剂 JE-VC 可提供至少 1-2 年的良好保护。在先前接种过 JE-MB 的成年人中接种一剂 JE-VC 的好处包括在旅行前完成重新接种的时间更短、不良反应风险降低和成本降低。
