Patients with critical COVID-19 had a lower absolute number of Th1 cells (19.18 (6.17-78.71) vs 100.05 (52.23-240.89), P<0.0001), whilst mild/moderate patients showed higher amounts of CD8+ effector memory T cells in comparison to severe and critical COVID-19 (34.45 (17.28-41.53) vs 22.29 (5.16-28.58) vs 1.25 (0.31-2.41), P=0.0002). Here, CD8A is linked to COVID-19.