New-onset seropositive rheumatoid arthritis following SARS-COV-2 infection and after COVID-19 vaccination

Shortly after the outbreak of atypical pneumonia due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causative agent of COVID-19, reports have emerged regarding the presence of immunological phenomena and autoimmune rheumatic diseases, including new-onset seropositive rheumatoid arthritis (RA). Within less than 12 months of the epidemic, the Pfizer and Moderna mRNA vaccines demonstrated an efficacy of over 95%. With the time, side effects have also been documented. This study aimed to analyze patients who were diagnosed as RA following SARS-CoV-2 infection and after vaccination against COVID-19. The major characteristics of these patients are: polyarthritis predominantely of small joints; presence of anti-citrulline protein antibody in 94% and the combination with rheumatoid factor was of 86%; serum levels of inflammatory markers (C-reactive protein, erythrocyte sedimentation rate) increased; the time interval between the viral infection or vaccination and the onset was 1 to 6 weeks; predominance in women, 77% of cases; six cases had pneumonia following SARS-CoV-2 vs 0 after COVID-19 vaccine; joint symptoms presented after the second dose in 10 (67%)/15 cases: two patients previously seronegative eventually developed seropositive RA; and there was a personal or family history of autoimmune diseases in 9 cases. Remission induction was achieved with methotrexate, with or without glucocorticoids, other disease-modifying antirheumatic drugs, and biological agents. Only 1 patient died of COVID-19. These findings show that in a limited number of cases, COVID-19 causes autoimmunity, possibly through molecular mimicry, adjuvants, or the activation of autoreactive T cells.