Table_2_Comparative SARS-CoV-2 Omicron BA.5 variant and D614G-Wuhan strain infections in ferrets: insights into attenuation and disease progression during subclinical to mild COVID-19.XLSX

IntroductionAs the SARS-CoV-2 virus continues to evolve and new variants emerge, it becomes crucial to understand the comparative pathological and immunological responses elicited by different strains. This study focuses on the original Wuhan strain and the Omicron variant, which have demonstrated significant differences in clinical outcomes and immune responses.
MethodsWe employed ferrets as an experimental model to assess the D614G variant (a derivative of the Wuhan strain) and the Omicron BA.5 variant. Each variant was inoculated into separate groups of ferrets to compare disease severity, viral dissemination, and immune responses.
ResultsThe D614G variant induced more severe disease and greater viral spread than the Omicron variant. Notably, ferrets infected with the D614G variant exhibited a robust neutralizing antibody response, whereas those infected with the Omicron variant failed to produce a detectable neutralizing antibody response. Despite the clearance of the virus from nearly all tissues by 7 days post-infection, an increase in pathological lesions was observed from 14 to 21 days, particularly in those infected with the D614G variant, suggesting a sustained immune response even after viral clearance.
DiscussionThese findings underscore the adaptability of SARS-CoV-2 and illuminate how susceptibility and clinical manifestations vary across different strains and species. The results emphasize the necessity of considering both the direct effects of viral infection and the indirect, often prolonged, impacts of the immune response in evaluating the outcomes of SARS-CoV-2 infections.

引言
随着严重急性呼吸综合征冠状病毒2（SARS-CoV-2）持续进化并不断出现新的变异株，解析不同毒株诱导的病理与免疫应答差异至关重要。本研究聚焦于原始武汉株与奥密克戎变异株（Omicron variant），二者在临床转归与免疫应答方面均表现出显著差异。

实验方法
本研究以雪貂为实验模型，对D614G变异株（武汉株的衍生毒株）与奥密克戎BA.5变异株进行评估。将两种变异株分别接种至不同组别雪貂，以比较疾病严重程度、病毒播散能力与免疫应答水平。

实验结果
相较于奥密克戎变异株，D614G变异株可诱发更严重的疾病与更广泛的病毒播散。值得注意的是，感染D614G变异株的雪貂可产生强烈的中和抗体应答，而感染奥密克戎变异株的雪貂则无法检测到中和抗体应答。尽管感染后7天即可在几乎所有组织中清除病毒，但在感染后14至21天观察到病理损伤加重，尤以D614G变异株感染组为甚，这表明即便病毒已被清除，免疫应答仍可持续存在。

讨论
本研究结果凸显了严重急性呼吸综合征冠状病毒2的适应性，并阐明了不同毒株与宿主物种间的易感性及临床表现差异。研究结果强调，在评估严重急性呼吸综合征冠状病毒2感染的转归时，需同时考虑病毒感染的直接效应与免疫应答所介导的间接（通常为持续性）影响。