CD4 and COVID-19: S1D); this pattern was reflected in absolute numbers estimated from the clinical data, where both CD4 and CD8 T cell counts in COVID-19 patients were lower than the clinical reference range, though the effect was more prominent for CD8 T cells (49 of 61 individuals with below-normal levels) than for CD4 T cells (38 of 61 individuals with below-normal levels) (fig.