From the Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samut Prakan, Thailand.
Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
Pediatr Infect Dis J. 2021 Mar 1;40(3):264-268. doi: 10.1097/INF.0000000000003007.
Children and young adults undergoing hematopoietic stem cell transplantation (HSCT) typically lose their immunity to vaccine-preventable diseases, including Japanese encephalitis (JE). Revaccination against JE in this population has not been well characterized.
This prospective study evaluated the immunogenicity of inactivated Vero cell culture-derived JE vaccine in children and young adults (<25 years of age) who had completed HSCT >1 year prior. Each patient received inactivated Vero cell culture-derived JE vaccine at enrollment and 1 month after enrollment, as well as a booster dose 13 months after enrollment. Serum JE plaque reduction neutralization test and JE-specific T lymphocyte count assay were performed at baseline, 1 month after the second dose, on the day of the booster dose, and 1 month after the booster dose.
Thirty-seven patients were enrolled. At baseline, 15 patients (40.5%) had plaque reduction neutralization titer >10, which is considered protective. Among 22 seronegative patients, 15 (68.2%) and 19 (86.4%) exhibited seroconversion after revaccination and booster dose, respectively. Median JE-specific T lymphocyte counts also increased. Twenty of 111 (18.0%) vaccination doses resulted in self-limiting side effects.
The inactivated Vero cell culture-derived JE vaccine may be safe and effective for immunization against JE virus in children and young adults who have undergone HSCT.
接受造血干细胞移植（HSCT）的儿童和青少年通常会失去对疫苗可预防疾病（包括日本脑炎[JE]）的免疫力。在这一人群中，针对 JE 的复种尚未得到很好的描述。
本前瞻性研究评估了已完成 HSCT>1 年的儿童和青少年（<25 岁）中使用灭活vero 细胞培养衍生 JE 疫苗的免疫原性。每位患者在入组时和入组后 1 个月接受灭活vero 细胞培养衍生 JE 疫苗，以及在入组后 13 个月接受加强剂量。在基线、第二剂后 1 个月、加强剂量当天和加强剂量后 1 个月进行 JE 病毒中和抗体滴度和 JE 特异性 T 淋巴细胞计数检测。
共入组 37 例患者。基线时，15 例患者（40.5%）的中和抗体滴度>10，被认为具有保护作用。在 22 例血清阴性的患者中，15 例（68.2%）和 19 例（86.4%）在复种和加强剂量后分别出现血清学转换。JE 特异性 T 淋巴细胞计数也中位数增加。111 剂疫苗中有 20 剂（18.0%）导致自限性副作用。
灭活 vero 细胞培养衍生 JE 疫苗对接受过 HSCT 的儿童和青少年预防 JE 病毒可能是安全有效的。
