Autoantibody and disease control stability following mRNA COVID-19 vaccination in rheumatoid arthritis: an observational cohort study.

To evaluate the long-term impact of mRNA-based COVID-19 vaccination on autoantibody titers, rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA), and disease control in rheumatoid arthritis (RA). RA patients with at least five visits before COVID-19 vaccination started were included and categorized by their vaccination status. Changes in RF and ACPA titers were analyzed using generalized linear mixed models to assess intra-patient trends over up to seven vaccine doses. Comparisons of autoantibody titers, seroconversion rates, and disease flares between vaccinated and non-vaccinated patients were performed using weighted generalized linear models with propensity score overlap weighting to adjust for confounding. Among 427 patients (359 vaccinated, 68 non-vaccinated), RF showed a slight but statistically significant decrease after repeated mRNA vaccinations (p < 0.001), while ACPA remained stable (p = 0.325). No significant differences in RF or ACPA were observed between the vaccinated and non-vaccinated patients after covariate adjustment. RF seroconversion occurred in 19.1% of RF-negative vaccinated patients and 11.8% of non-vaccinated patients and ACPA seroconversion occurred in 8.2% of ACPA-negative vaccinated patients and 13.3% of non-vaccinated patients, showing no statistically significant difference. No significant differences were found in the number of disease flares (3.82 ± 4.05 in vaccinated, 4.73 ± 5.38 in non-vaccinated). mRNA-based COVID-19 vaccination did not lead to increased autoantibody titers, seroconversion rates, or disease flare. Instead, successive vaccine doses led to a significant RF decrease, suggesting that the mRNA vaccine has a potentially beneficial immunomodulatory effect and support the safety of repeated boosters in RA.