CD4 and COVID-19: Accordingly, CD4+ Th1 cells are essential for an adequate antiviral response during SARS-CoV-2 acute infection (62–64), while COVID-19 severity has been associated with a predominant extracellular response mostly mediated by high levels of CD4+ Th2 cells (65) and cytokines such as IL-2 and IL-6 (66) that are initiators of the “cytokine storm” and create a pro-inflammatory environment with low efficacy for viral clearance (67).