Severe and critical COVID-19 have been also associated with cytopenia, mostly of CD4+ T lymphocytes, as well as with excessive exhaustion of natural killer (NK) and CD8+ T cells, which results in an immunocompromised state that is unable to clear the infection, in addition to the development of serious complications such as cytokine storm and thrombotic events [7]. This evidence concerns the gene CD8A and COVID-19.