CD44 and COVID-19: Even though COVID-19 patients have shown an increase in the expression of molecules related to T CD4+ activation, such as CD69, CD38, and CD44, molecules related to their function, such as intracellular IFN-γ, IL-2, and TNF-α, are reduced, especially in individuals with a more severe stage of the disease (9, 170), indicating an impairment of polyfunctional T cells.