COVID-19 vaccine booster uptake and effectiveness among persons with systemic autoimmune and rheumatic diseases

Objective To assess COVID-19 booster uptake and vaccine effectiveness (VE) in reducing COVID-19 hospitalization in persons with systemic autoimmune and rheumatic diseases (SARDs). Methods Adult patients with SARDs receiving disease modifying anti-rheumatic drugs at four health systems in the United States were identified retrospectively. Exposures were: 1) receipt of an additional dose of monovalent COVID-19 vaccine prior to January 1, 2022, with follow-up to August 31, 2022; and (2) receipt of bivalent COVID-19 vaccine between September 1, 2022 to August 31, 2023. Results Among 201,165 patients with SARDs, 126,756 (63%) had received one monovalent booster as of January 1, 2022. During 94,842 person-years of follow-up, the COVID-19 hospitalization rate was 15.6 per 1000 person-years among those who had received a monovalent booster versus 20.1 per 1000 person-years among those who had not, with an adjusted VE of 38% (95% confidence interval [CI] 31% - 44%) and a number needed to vaccinate of 267 (CI 230-325). Among 246,991 patients with SARDs with 233,622 person-years of follow-up in the bivalent study period, the COVID-19 hospitalization rate was 7.9 per 1000 person-years for the 87,906 (36%) patients who received the bivalent vaccine, versus 10.2 per 1000 person-years for the patients who did not. The adjusted VE of the bivalent vaccine was 32% (CI 24% - 39%) with a number needed to vaccinate of 617 (CI 500-838). Conclusion COVID-19 booster vaccinations provided significant protection against severe COVID-19 in persons with autoimmune disease. Thus, increasing vaccine uptake should be prioritized in this high-risk immunocompromised population.