Zinc is considered a “guardian” for the body, as it plays an essential role in the functioning of the immune system [115], plays a central role in cell growth and differentiation of the immune system cells that have rapid differentiation and turnover [116]. Most of the studies have recently reported a very interesting evaluation of the function of zinc in antiviral immunity, suggesting how it can play a role in host defense against RNA viruses, inhibiting the RNA polymerase required by RNA viruses (such as coronaviruses) to replicate [117]. The zinc-binding metallothionein seems to play an important role in antiviral defense. Zinc deficiency has a marked impact on bone marrow, decreasing the number of immune precursor cells, with reduced output of naive B lymphocytes, and causes thymic atrophy, reducing the output of naive T lymphocytes. Therefore, zinc is essential for cell growth and differentiation of immune cells, helping to modulate the cytokine release and trigger CD8+ T cell proliferation.