Lee Ah-Ra, Kim Woo-Jin, Choi Haeyoun, Kim Sang-Hyun, Hong Su-Yeon, Shim Sang-Mu, Lee Hee Il, Song Jae Min, Kim Seong-Jun, Ishikawa Tomohiro, Kang Ji-Man, Eom Hyeon-Seok, Seo Sang-Uk
Department of Medical Sciences, Graduate School of The Catholic University of Korea, Seoul, Republic of Korea.
Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
J Infect Dis. 2025 Jun 2;231(5):1281-1289. doi: 10.1093/infdis/jiae589.
Japanese encephalitis (JE) has been predominantly controlled through vaccination. However, the isolation of JE virus (JEV) genotype V (GV) in China in 2009, and the subsequent alarming increase in JE cases in the Republic of Korea since 2010, present a new challenge.
Serum samples from individuals vaccinated with genotype III (GIII)-based JE vaccines were analyzed for neutralizing seroresponse to GV isolates.
Serum from immunocompromised pediatric patients vaccinated with an inactivated JE vaccine showed higher 50% plaque reduction neutralization test geometric mean titer (GMT) against GIII Nakayama (11 358; 95% confidence interval [CI], 1790-29 658), but lower GMTs against GV isolates: GV Muar (499; 95% CI, 0-2437), GV 43279 (308; 95% CI, 159-582), and GV 43413 (231; 95% CI, 108-738). Similarly, 32 healthy volunteers receiving a live attenuated JE vaccine achieved 100% seroprotection against GIII Nakayama with GMT of 338 (95% CI, 304-651) at 1 month postvaccination. However, GMTs against GV isolates were 123 (95% CI, 102-446) for GV Muar, 81 (95% CI, 63-168) for GV 43279, and 107 (95% CI, 100-322) for GV 43413, not achieving 100% seroprotection against these isolates. At 6 months postvaccination, GMT against Nakayama increased to 696 (95% CI, 409-2353), while remaining similar for GV isolates.
Our study underscores that current GIII-based vaccines do not provide comparable protection against GV JEVs, impacting individuals in both current and potential endemic regions, as well as travelers to these regions.
乙型脑炎（JE）主要通过疫苗接种得到控制。然而，2009年中国分离出乙型脑炎病毒（JEV）基因型V（GV），且自2010年以来韩国乙型脑炎病例惊人地增加，这带来了新的挑战。
分析接种基于基因型III（GIII）的乙型脑炎疫苗的个体的血清样本，以检测其对GV分离株的中和血清反应。
接种灭活乙型脑炎疫苗的免疫功能低下儿科患者的血清对GIII 中山株显示出较高的50%蚀斑减少中和试验几何平均滴度（GMT）（11358；95%置信区间[CI]，1790 - 29658），但对GV分离株的GMT较低：GV 麻坡株（499；95% CI，0 - 2437）、GV 43279株（308；95% CI，159 - 582）和GV 43413株（231；95% CI，108 - 738）。同样，32名接种减毒活乙型脑炎疫苗的健康志愿者在接种后1个月对GIII 中山株实现了100%血清保护，GMT为338（95% CI，304 - 651）。然而，对GV分离株的GMT分别为：GV 麻坡株123（95% CI，102 - 446）、GV 43279株81（95% CI，63 - 168）和GV 43413株107（95% CI，100 - 322），未对这些分离株实现100%血清保护。接种后6个月，对中山株的GMT增至696（95% CI，409 - 2353），而对GV分离株的GMT保持相似。
我们的研究强调，当前基于GIII的疫苗对GV JEVs不能提供同等的保护，这对当前和潜在的流行地区的个体以及前往这些地区的旅行者都会产生影响。
