The CD4+ cell count reflects the immunocompetence level [32], and the median value was higher than 500 cells/mm3 in all patients except for those with a low response, and at least one HIV RNA plasma value of >20 copies/mL (OV); however, they had a median value of 427 cells/mm3, which is more than double the threshold of 200 CD4+ cells/mm3 associated with a low humoral response to the COVID-19 vaccine [31,33]. This evidence concerns the gene CD4 and COVID-19.