CD4 and COVID-19: When the Th polarization of CD4+ T-cells was studied, COVID-19 patients compared to healthy controls showed a decreased median in the proportion of Th1: 4.8% (3.3–6.5) vs. 6.4% (4.9–8.2) (p = 0.011) and Th17: 4% (3.1–5.7) vs. 7% (3–10.6) (p = 0.018).