Um Jihye, Nix Chad Douglas, Messer William Bill, Zhu Yerun, Park Jun-Sun, Collins Matthew Harmon, Chin BumSik
Public Health Research Institute, National Medical Center, Korea.
Department of Public Health, Korea University Graduate School, Korea.
Jpn J Infect Dis. 2025 Mar 21;78(2):79-84. doi: 10.7883/yoken.JJID.2023.290. Epub 2024 Nov 29.
Although a live-attenuated yellow fever (YF) vaccine is known to elicit durable immunity, antibody titers may wane after vaccination. This study evaluated long-term immunity after vaccination against YF among individuals who resided in Korea and were vaccinated with YF virus- 17D prior to international travel. Serum was collected between December 2018 and December 2019 at the National Medical Center, Republic of Korea, from YF vaccine recipients who had been vaccinated for more than five years prior to sample collection. Long-term immunity against YF was assessed using three serological assays: IgG enzyme-linked immunosorbent assay (ELISA), immunofluorescence assay (IFA), and the focus reduction neutralization test (FRNT). Sixty-seven patients were enrolled in this study. The overall positivity rates for 50% focus reduction neutralization test (FRNT ), IFA, and ELISA in a time-variable cross-sectional sample of the cohort were 97.0%, 86.6%, and 26.9%, respectively. While 93.8% (15/16) of samples collected ≥10 years post-vaccination remained positive by FRNT , a significant inverse correlation was observed between FRNT titer and interval after vaccination (R = - 0.385, P = 0.001). Humoral immunity against YF was well preserved among Korean individuals who were vaccinated more than five years ago. IFA testing yielded results similar to those of FRNT testing, which may justify the further development of IFA to screen for waning immunity among those with previous YF vaccination.
尽管减毒活黄热病（YF）疫苗已知能引发持久免疫力，但接种疫苗后抗体滴度可能会下降。本研究评估了居住在韩国且在国际旅行前接种了YF病毒17D疫苗的个体接种YF疫苗后的长期免疫力。2018年12月至2019年12月期间，在大韩民国国家医疗中心从样本采集前已接种YF疫苗超过五年的YF疫苗接种者中采集血清。使用三种血清学检测方法评估对YF的长期免疫力：IgG酶联免疫吸附测定（ELISA）、免疫荧光测定（IFA）和蚀斑减少中和试验（FRNT）。本研究共纳入67例患者。该队列的时间可变横断面样本中，50%蚀斑减少中和试验（FRNT）、IFA和ELISA的总体阳性率分别为97.0%、86.6%和26.9%。虽然接种疫苗≥10年后采集的样本中有93.8%（15/16）通过FRNT检测仍呈阳性，但观察到FRNT滴度与接种后间隔时间之间存在显著的负相关（R = -0.385，P = 0.001）。在五年多前接种疫苗的韩国个体中，对YF的体液免疫得到了很好的保留。IFA检测结果与FRNT检测结果相似，这可能为进一步开发IFA以筛查既往接种YF疫苗者免疫力下降情况提供依据。
