Clinical characteristics and outcomes of COVID-19 breakthrough infections among vaccinated patients with systemic autoimmune rheumatic diseases

Abstract Objective To describe the characteristics of COVID-19 vaccine breakthrough infections among systemic autoimmune rheumatic disease (SARD) patients. Methods We identified SARDs patients in a large healthcare system with COVID-19 vaccination ≥14 days prior to a positive SARS-CoV-2 molecular test. Details of the patient’s SARD, vaccination status, and COVID-19 infection were extracted. Results Of 340 confirmed COVID-19 infections among SARDs patients between December 11th, 2020 (date of first COVID-19 vaccine approval in the US) and July 30th, 2021, we identified 16 breakthrough infections. Seven (44%) received the Pfizer-BioNtech vaccine, five (31%) received the Moderna vaccine, and four (25%) received the Janssen/Johnson & Johnson vaccine. The most common SARDs included rheumatoid arthritis (6, 38%), inflammatory myopathy (3, 19%), and systemic lupus erythematosus (3, 19%). Rituximab (5, 31%), glucocorticoids (4, 25%), and mycophenolate mofetil (4, 25%) were the most frequent treatments. Among the breakthrough infections, 15 (93%) were symptomatic, six (38%) were hospitalized, one (6%) required mechanical ventilation, and two (13%) died. Conclusions Symptomatic, including severe, breakthrough infections were observed in SARDs patients; many were on treatments associated with attenuated antibody responses to vaccination. Further studies are needed to determine the rate of breakthrough infection associated with SARD treatments and other features. Key messages What is already known about this subject? Breakthrough infections following COVID-19 vaccination are expected but some patients with systemic autoimmune rheumatic diseases (SARDs) may be at higher risk because of blunted antibody responses to vaccination associated with rheumatic disease treatments and other factors that remain poorly understood. What does this study add? We identify and describe 16 COVID-19 vaccine breakthrough infections within the Mass General Brigham system between December 11th, 2020 and June 26th, 2021. The vast majority of cases were symptomatic and two were fatal. How might this impact on clinical practice or future developments? This study complements observations regarding the attenuated antibody response to COVID-19 vaccination in patients with SARDs by identifying serious clinical outcomes from breakthrough infections in patients receiving DMARDs that have been reported to have blunted vaccine responses. Our study identifies characteristics of COVID-19 breakthrough infections that may guide the prioritization of booster vaccines and other risk-mitigating strategies in patients with SARDs.