Humoral and T Cell Response to SARS‐CoV‐2 Vaccination in Patients With Rheumatoid Arthritis

Objective The objective of this study was to assess the SARS‐CoV‐2–specific humoral and T cell response after a two‐dose regimen of SARS‐CoV‐2 vaccine in patients with rheumatoid arthritis (RA). Methods In this observational study, patients with RA who are ≥18 years of age and vaccinated for SARS‐CoV‐2 according to the Argentine National Health Ministry's vaccination strategy were included. Anti–SARS‐CoV‐2 immunoglobulin G (IgG) antibodies (ELISA‐COVIDAR test), neutralizing activity (cytotoxicity in VERO cells), and specific T cell response (IFN‐γ ELISpot Assay) were assessed after the first and second dose. Results A total of 120 patients with RA were included. Mostly, homologous regimens were used, including Gam‐COVID‐Vac (27.5%), ChAdOx1 (24.2%), and BBIBP‐CorV (22.5%). The most frequent combination was Gam‐COVID‐Vac/mRNA‐1273 (21.7%). After the second dose, 81.7% presented with anti–SARS‐CoV‐2 antibodies, 70.0% presented with neutralizing activity, and 65.3% presented with specific T cell response. The use of BBIBP‐CorV and treatment with abatacept (ABA) and rituximab (RTX) were associated with undetectable antibodies and no neutralizing activity after two doses. BBIBP‐CorV was also associated with the absence of T cell response. The total incidence of adverse events was 357.1 events per 1,000 doses, significantly lower with BBIBP‐CorV (166.7 events per 1,000 doses, P