Immunogenicity induced by two and three doses of the BNT162b2 mRNA vaccine in patients with autoimmune inflammatory rheumatic diseases and immunocompetent controls: a longitudinal multicentre study

ObjectivesTo evaluate long-term kinetics of the BNT162b2 mRNA vaccine-induced immune response in adult patients with autoimmune inflammatory rheumatic diseases (AIIRD) and immunocompetent controls.MethodsA prospective multicentre study investigated serum anti-SARS-CoV-2 S1/S2 IgG titre at 2–6 weeks (AIIRD n=720, controls n=122) and 6 months (AIIRD n=628, controls n=116) after the second vaccine, and 2–6 weeks after the third vaccine dose (AIIRD n=169, controls n=45). T-cell immune response to the third vaccine was evaluated in a small sample.ResultsThe two-dose vaccine regimen induced a higher humoral response in controls compared with patients, postvaccination seropositivity rates of 100% versus 84.72%, pConclusionsThe two-dose BNTb262 regimen was associated with similar clinical efficacy and similar waning of the humoral response over 6 months among patients with AIIRD and controls. The third vaccine dose restored the humoral response in all of the controls and the majority of patients.