CD4 and COVID-19: Of the T helper cell compartment, Th1-type cells were low (p < 0.001) and Th2-type cells were high (p = 0.001), leading to a reduced Th1/Th2 ratio (1.19 vs. 6.46 of controls; p < 0.001); Th17-type cells were higher in active COVID-19 patients and Th9 marginally increased; however, the ratios Th1/Th17 and Th9/Th17 (p < 0.05) were both very low, whereas the Th17/CD4+ Treg ratio was increased, suggesting a differential Th cell polarization between active COVID-19 patients and controls.