Infection with SARS-CoV-2 causes wide range of disease severities from asymptomatic to life-threatening disease. Understanding the contribution of immunological traits in immunity against SARS-CoV-2 and in protection against severe COVID-19 could result in effective measures to prevent development of severe disease. While the role of cytokines and antibodies has been thoroughly studied, this is not the case for T cells. In this review, the association between T cells and COVID-19 disease severity and protection upon reexposure is discussed. While infiltration of overactivated cytotoxic T cells might be harmful in the infected tissue, fast responding T cells are important in the protection against severe COVID-19. This protection could even be viable in the long term as long-living memory T cells seem to be stabilized and mutations do not appear to have a large impact on T cell responses. Thus, after vaccination and infections, memory T cells should be able to help prevent onset of severe disease for most cases. Considering this, it would be useful to add N or M proteins in vaccinations, alongside the S protein which is currently used, as this results in a broader T cell response.

感染 SARS-CoV-2 会导致各种严重程度的疾病，从无症状到危及生命的疾病。了解免疫学特性在抵抗 SARS-CoV-2 和预防重症 COVID-19 方面的作用可能会导致采取有效措施来预防重症的发展。虽然细胞因子和抗体的作用已得到深入研究，但 T 细胞的情况并非如此。在这篇综述中，讨论了 T 细胞与 COVID-19 疾病严重程度和再次暴露后的保护之间的关联。虽然过度活化的细胞毒性 T 细胞浸润在受感染的组织中可能有害，但快速反应的 T 细胞对于预防严重的 COVID-19 很重要。这种保护在长期内甚至可能是可行的，因为长寿记忆 T 细胞似乎已稳定下来，并且突变似乎不会对 T 细胞反应产生很大影响。因此，在接种疫苗和感染后，记忆 T 细胞应该能够帮助预防大多数情况下严重疾病的发作。考虑到这一点，在疫苗接种中添加 N 或 M 蛋白以及目前使用的 S 蛋白将很有用，因为这会导致更广泛的 T 细胞反应。