The results of a study performed by Lotan et al. among BNT162b2 mRNA vaccinated MS patients on IFN-β, dimethyl fumarate, natalizumab, ocrelizumab, teriflunomide, fingolimod, cladribine, glatiramer acetate, or corticosteroids showed that 60% of cases who received just the first dose of the vaccine, 58.1% just after the second dose, and 9.7% after both doses reported new or worsening neurological symptoms [99]. This evidence concerns the gene IFNB1 and myeloid sarcoma.