CD4 and COVID-19: Similarly, the numbers of total CD4+ and CD8+ T cells within CD3+-gated cells were reduced early in the two groups of unvaccinated severely ill COVID-19 patients and unvaccinated COVID-19 patients with fatal outcomes (i.e., patients with severity 3, 4, and 5) compared to the three groups of unvaccinated asymptomatic COVID-19 patients with low to no severe disease (Figure 3C—left column graph).