CD8A and COVID-19: Subsequent analysis on phenotypic markers revealed that the majority of the SARS-CoV-2-specific CD8+ T cells were CD45RA+CCR7– terminally differentiated effector memory cells (TEMRA), whereas CD45RA–CCR7– effector memory T cells (TEM) accounted for only one-fourth of the total antigen-specific CD8+ T cells (Fig. 3e), similar to that from recovered COVID-19 patients27.