COVID‐19 Vaccination Before Initiating Rituximab Treatment Induces Strong Serological Response in Autoimmune Rheumatic Disease, Reducing Post‐Pandemic Concerns About the Impact of Rituximab.

Objective: Rituximab (RTX)‐treated patients exhibit suboptimal responses to COVID‐19 vaccines. However, existing research primarily involves patients already receiving RTX when vaccines were introduced, failing to account for the current landscape where patients are vaccinated before initiating RTX. Our objective was to compare the serological response to COVID‐19 vaccines in patients vaccinated before or after RTX initiation. Methods: We included 254 RTX‐treated patients with autoimmune inflammatory rheumatic diseases (AIIRDs) and 113 blood donors (BDs) in a retrospective, observational cohort study. Patients were categorized based on the timing of RTX treatment relative to primary COVID‐19 vaccination. Serological vaccine responses were assessed using three immunoassays, and logistic regression analysis was used to identify predictors of serological response. Results: Patients vaccinated before initiating RTX treatment had significantly higher seroconversion rates of SARS‐CoV‐2 immunoglobulin G (87%) and neutralizing antibodies (91%) compared with those receiving RTX before and after vaccination (n = 132) (61% and 65%, respectively). In the logistic regression analysis, a positive serological response was associated with the number of vaccines administered >9 months after the last RTX treatment. Patients receiving the highest number of vaccines with >9 months after RTX showed a response comparable to that of the BDs. Conclusion: Vaccinating before RTX initiation yields a robust serological response in patients with AIIRDs. Furthermore, we highlight the reversibility of antibody impairment after RTX treatment cessation, provided that adequate vaccinations occur within a minimum of 9 months after RTX. Our findings offer essential insights for clinical decision‐making regarding COVID‐19 vaccination and RTX treatment, alleviating concerns about future RTX use. [ABSTRACT FROM AUTHOR]