Disease activity and humoral response in patients with inflammatory rheumatic diseases after two doses of the Pfizer mRNA vaccine against SARS-CoV-2

Background The registration trials of messenger RNA (mRNA) vaccines against SARS-CoV-2 did not address patients with inflammatory rheumatic diseases (IRD). Objective To assess the humoral response after two doses mRNA vaccine SARS-CoV-2, in IRD treated immunomodulating drugs and impact on activity. Methods Consecutive at rheumatology institute, who received their first (Pfizer) vaccine, were recruited to study, routine visit. They reassessed 4–6 weeks receiving second dose blood samples obtained for serology. activity assessment side effects documented during both visits. IgG antibodies (Abs) detected using II Quant (Abbott) assay. Results Two hundred sixty-four stable disease, (mean(SD) age 57.6 (13.18) years, disease duration 11.06 (7.42) years), recruited. immunomodulatory therapy was modified before or vaccination. After vaccination, 227 (86%) mounted Ab (mean (SD) 5830.8 (8937) AU/mL) 37 (14%) not, 22/37 B cell-depleting agents. reported minor. remained all patients. Conclusions vast majority developed a significant following administration Pfizer virus. Only minor no apparent noted.