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.

中文翻译：

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根据年轻健康成年人对 2023 年底流通的变异病毒的免疫反应，告知需要 SARS-CoV-2 加强剂

背景 由于新的免疫逃避 SARS-CoV-2 变体和异质免疫，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 初级疫苗系列，并接种了异质 SARS-CoV-2 疫苗，并且有 3 种先前主要变种（Ancestral、Delta）的感染史。 、BA.5）和 2023 年末的 3 个流行变种（XBB.1.5、EG.5 和 BA.2.86）。根据最常见的时间（12 个月内或之后）和类型（疫苗或感染）进行分析近期曝光。结果 与之前的变体相比，针对循环变体的结合抗体、中和抗体、记忆 B 细胞和 CD8+ T 细胞显着减少。对于最近一次暴露于入组后超过 12 个月的患者，抗体反应的降低更为明显。相比之下，所有测试变体的 CD4+ T 细胞反应基本一致。最近接触的类型并不是决定当前免疫反应强度的重要因素。结论 使用基于 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。需要持续监测对新出现变异的免疫反应，以了解疫苗的成分和时机。