背景:由于新的免疫规避性SARS-CoV-2变体和异质性免疫,COVID-19仍然是全球公共卫生挑战。
方法:在这项横断面研究中,我们评估了美国现役人员的适应性免疫反应,这些人员完成了COVID-19主要疫苗系列,并且具有异质的SARS-CoV-2疫苗接种和感染史,Delta,BA.5)和3个循环变体(XBB.1.5,EG.5和BA.2.86)在2023年末。根据最近暴露的时间(12个月内或超过12个月)和类型(疫苗或感染)进行分析。
结果:在结合抗体中观察到显著减少,中和抗体,记忆B细胞,和CD8+T细胞针对循环变体与先前变体相比。抗体反应的减少在最近一次暴露超过12个月的人中更为明显。相比之下,所有受试变异体的CD4+T细胞应答基本一致.最近的暴露类型不是确定当前免疫反应程度的重要因素。
结论:施用基于XBB.1.5的加强剂可能会增强针对SARS-CoV-2循环谱系的交叉反应性体液反应。需要持续监测对新兴变体的免疫反应以告知疫苗组成和时机。
BACKGROUND: COVID-19 remains a global public health challenge due to new immune-evasive SARS-CoV-2 variants and heterogeneous immunity.
METHODS: In this cross-sectional study, we evaluated the adaptive immune responses in U.S. active-duty personnel who completed a COVID-19 primary vaccine series and with heterogenous SARS-CoV-2 vaccination and infection histories to 3 previously dominant variants (Ancestral, Delta, BA.5) and 3 circulating variants (XBB.1.5, EG.5, and BA.2.86) in late 2023. Analyses were performed based upon timing (within or beyond 12 months) and type (vaccine or infection) of the most recent exposure.
RESULTS: Significant reduction was observed in binding antibodies, neutralization antibodies, memory B cells, and CD8+ T cells against circulating variants compared to previous variants. The reduction in antibody response was more pronounced in those whose most recent exposure was greater than 12 months from enrollment. In contrast, the CD4+ T cell response was largely consistent across all tested variants. The type of most recent exposure was not a significant factor in determining the magnitude of current immune responses.
CONCLUSIONS: Administration of the XBB.1.5-based booster is likely to enhance cross-reactive humoral responses against SARS-CoV-2 circulating lineages. Ongoing surveillance of immune responses to emerging variants is needed for informing vaccine composition and timing.