CD8A and COVID-19: A functional study of the interferon-γ (IFN-γ) secretion by T cells stimulated with a mixture of SARS-CoV-2 derived peptides (S, M and N) show a significant difference in the CD8+T cell production of IFN-γ between HD and moderate/severe COVID19 as well as between mild and moderate/severe COVID19 patients (Figure 1F).