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

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 at least 14 days prior to a positive SARS-CoV-2 molecular test. Details of the SARD diagnosis, 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.