CD4 and infection: Similarly, higher frequencies of functional IFN-γ-producing CD4+ T cells ASYMP COVID-19 patients (mean SFCs > 25 per 1 × 106 pulmonary immune cells) were detected, irrespective of infection with Beta (p < 0.5, Figure 1C, left panel) or Omicron (p < 0., Figure 1C, right panel) variants, whereas reduced frequencies of IFN-γ-producing CD4+ T cells were detected in SYMP COVID-19 patients, irrespective of infection with Beta (p < 0.5, Figure 1C, left panel) or Omicron (p < 0., Figure 1C, right panel) variants.