CD8A and COVID-19: Frequencies of reactive CD4+ and CD8+ T cells were comparable among the three groups in response to SARS-CoV-2 peptides (Figures 1A, B), whereas HC had significantly higher frequencies of reactive CD4+ T cells in response to HCoV-229E S C-term (Ab−: p = 0,05; Ab+ p = 0.02) and HCoV-OC43 S N-term (Ab−: p = 0.03; Ab+: p = 0.03) compared to post COVID-19 (Figure 1A).