(b–c) Count per μl of blood and frequency of total CD8+ T cells (a) and central memory (CM), effector memory (EM), effector memory CD45RA+ (EMRA), stem cell memory (SCM), naïve CD8+ T cells (c) before (T0) and 7 days after first (T1) and second vaccination (T3) in SARS-CoV-2 experienced RA-MTX patients, MS-OCR patients, and healthy control (HC). This evidence concerns the gene CD8A and rheumatoid arthritis.