Specifically, fingolimod, a sphingosine-1 phosphate receptor modulator, predominantly impairs IFN-γ-specific T-cell response (31–33), while the B-cell-depleting anti-CD20 monoclonal antibody, ocrelizumab, is mostly associated with reduced anti-receptor binding domain (RBD) and neutralizing antibody production after COVID-19 vaccination (34–37). This evidence concerns the gene IFNG and COVID-19.