ABSTRACT
Objective To determine prevalence and factors associated with flares post Coronavirus disease 2019 (COVID-19) mRNA vaccination in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and spondyloarthritis (SpA). Methods A retrospective multi-centre study was conducted (January 2021 to February 2022). Data were collected during index visit, defined as first post-vaccine visit in which the patient had a physician-defined flare, or if at least three months had elapsed since first vaccine dose, whichever came first. Factors associated with flares were identified using mixed effects Cox regression and expressed as hazard ratio (HR) and 95% confidence interval (CI). Results Total of 2377 patients were included (1563 RA, 415 PsA and 399 SpA). Among patients with RA, PsA and SpA, 21.3%, 24.1% and 21.8% experienced a flare respectively. Of those who experienced a flare, only 10.2%, 11.0% and 14.9% were severe in patients with RA, PsA and SpA respectively. Patients with low or moderate/ high disease were more likely to flare compared to those in remission in patients with RA only (HR: 1.68, 95% CI: 1.22 – 2.31; HR: 2.28, 95% CI: 1.50 – 3.48, respectively). Receiving the Moderna vaccine was associated with a higher HR of flare compared to the Pfizer vaccine in patients with PsA only (HR: 2.21, 95% CI: 1.20 – 4.08). Patients who had two vaccine doses were found to be less likely to flare (HR: 0.08, 95% CI: 0.06 – 0.10). HRs of flares were not significantly different among RA, PsA and SpA. Conclusion About one-fifth of patients experienced a disease flare post COVID-19 mRNA vaccination, but most flares were non-severe. Patients with active disease prior to vaccination should be monitored closely for disease flares, especially in patients with RA.