Background Vaccinations against SARS-CoV-2 represent a fundamental tool in controlling the pandemic. To date, data on the safety of anti-SARS-CoV-2 vaccines in patients with rare rheumatic diseases, such as systemic vasculitis, are limited.

Objectives In this study we aimed at evaluating the safety of anti-SARS-CoV-2 vaccines in a multicentric cohort of patients with systemic vasculitis.

Methods Patients with systemic vasculitis from two Rheumatology centres who had received anti-SARS-CoV-2 vaccine were retrospectively examined. The primary outcome was to evaluate, in this multi-centric cohort, the occurence of a disease flare after the administration of the vaccine, defined as development of clinical manifestations related to vasculitis with a concomitant increase in serum inflammatory markers. As a secondary outcome we aimed at evaluating, in a monocentric cohort of patients with vasculitis, the occurrence of adverse events (AEs) following vaccine administration compared to healthy controls (HC).

Results We examined 111 patients with systemic vasculitis (n=69 female, n=42 male), with a mean age of 64.3 (± 13) years. Sixty had ANCA-associated vasculitis (AAV), fourty-two had Giant-Cell Arterities (GCA), five had Periarteritis Nodosa, four had Takayasu’s arteritis. One-hundred and five patients received a mRNA vaccine and six a viral vector one. A disease flare occurred in only 2 patients (1.8%) after the first dose of a mRNA vaccine: both had AAV (microscopic poliangioitis) and developed a pulmunary disease flare (respiratory failure requiring hospitalization and treatment with high-dose glucocorticoids). Of note, one of these patients had multiple previous comorbidities, including a severe COPD. Multivaried analysis, adjusted for age and sex, performed in a single monocentric cohort of patients with systemic vasculitis [n=60 (39 AAV, 21 GCA), 37 female, 23 male, mean age 71 (± 12.5) years] demonstrated a statistically significant higher frequency of AEs in vasculitis patients compared to HC (p=0.015) after the first dose of vaccination. No significant differences in the frequency of AEs in vasculitis patients compared to HC after the second dose were detected. All the AEs were mild in both groups (malaise was the most frequently reported); no serious AEs were reported.

Conclusion Our data show a very low incidence of disease flares after the administration of anti-SARS-CoV-2 vaccines in patients with systemic vasculitis. Patients with systemic vasculitis seem more prone to develop mild AEs after the first dose of the vaccine. Taken together, this data suggest a good risk profile for anti-SARS-CoV-2 vaccine in patients with systemic vasculitis.

Disclosure of Interests None declared