High antibody response to two-dose SARS-CoV-2 messenger RNA vaccination in patients with rheumatic and musculoskeletal diseases

SARS-CoV-2 mRNA vaccination elicited high immunogenicity in immunocompetent people in the original vaccine trials,1 2 though recent studies have shown blunted immunogenicity in patients with rheumatic and musculoskeletal diseases (RMDs) after a single dose and case reports of non-response after two doses.3 4 We previously detailed antibody response in patients with RMD following the first dose of SARS-CoV-2 mRNA vaccination and herein report response and factors associated with response to two-dose vaccination in a larger cohort. As previously reported,3 patients aged ≥18 years old with RMD were recruited to participate in this prospective, observational cohort via social media outreach to national RMD organisations between 12 July 2020 and 16 March 2021. Demographics, diagnoses and therapeutic regimens were collected via participant report through the Research Electronic Data Capture tool. One month after dose 2 (D2), participants underwent SARS-CoV-2 antibody testing on the semiquantitative Roche Elecsys anti-SARS-CoV-2 S enzyme immunoassay, which measures total antibody (IgM and IgG) to the SARS-CoV-2 S receptor-binding domain (RBD) protein,5 the target of the mRNA vaccines. Results range from 250 U/mL with a positive response defined as >0.79 U/mL. Associations were evaluated using Fisher’s exact and Wilcoxon rank-sum tests. Participants provided informed consent. We studied 404 participants who received two doses of the SARS-CoV-2 mRNA vaccine (online supplemental table 1). The median (IQR) age was 44 (36–57), 96% were female, 9% were non-white, …