After vaccination, the IFN-γ SFU response was positive in 42 of 46 (91%) rituximab-treated patients with MS (with no history of a positive SARS-CoV-2 polymerase chain reaction test result) using the Mabtech peptide pool, and 38 of 46 patients (83%) using the in-house peptide pool. Here, IFNG is linked to myeloid sarcoma.