Immune responses elicited by viral infection or vaccination play key roles in the viral elimination and the prevention of reinfection, as well as the protection of healthy persons. As one of the most widely used Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, there have been increasing concerns about the necessity of additional doses of inactivated vaccines, due to the waning immune response several months after vaccination. To further optimize inactivated SARS-CoV-2 vaccines, we compared immune responses to SARS-CoV-2 elicited by natural infection and immunization with inactivated vaccines in the early phase. We observed the lower antibody levels against SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in the early phase of postvaccination with a slow increase, compared to the acute phase of SARS-CoV-2 natural infection. Specifically, IgA antibodies have the most significant differences. Moreover, we further analyzed cytokine expression between these two groups. A wide variety of cytokines presented high expression in the infected individuals, while a few cytokines were elicited by inactivated vaccines. The differences in antibody responses and cytokine levels between natural SARS-CoV-2 infection and vaccination with the inactivated vaccines may provide implications for the optimization of inactivated SARS-CoV-2 vaccines and the additional application of serological tests.

中文翻译：

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对自然 SARS-CoV-2 感染或疫苗接种的早期阶段的独特免疫反应


病毒感染或疫苗接种引起的免疫反应在消除病毒和预防再感染以及保护健康人方面发挥着关键作用。作为最广泛使用的严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 疫苗之一，由于接种疫苗几个月后免疫反应减弱，人们越来越担心是否需要额外剂量的灭活疫苗。为了进一步优化 SARS-CoV-2 灭活疫苗，我们比较了自然感染和早期灭活疫苗免疫对 SARS-CoV-2 引起的免疫反应。我们观察到，与 SARS-CoV-2 自然感染的急性期相比，在疫苗接种后的早期阶段，针对 SARS-CoV-2 刺突 (S) 和核衣壳 (N) 蛋白的抗体水平较低，且缓慢增加。具体而言，IgA 抗体具有最显着的差异。此外，我们进一步分析了这两组之间的细胞因子表达。多种细胞因子在感染个体中呈现高表达，而一些细胞因子是由灭活疫苗引发的。自然 SARS-CoV-2 感染和灭活疫苗接种之间抗体反应和细胞因子水平的差异可能为灭活 SARS-CoV-2 疫苗的优化和血清学检测的额外应用提供启示。