Predictors of Hospitalization in Breakthrough COVID-19 among Fully Vaccinated Individuals with Immune-Mediated Rheumatic Diseases: Data from Safer-Study

Breakthrough COVID-19 (occurring in fully vaccinated people) has been described. Data on its characteristics among immune mediated rheumatic disesases (IMRD) patients are scarce. This study describes breakthrough COVID-19 among IMRD patients participating of SAFER-study, a Brazilian multicentric cohort evaluating safety, effectiveness and immunogenicity of SARS-Cov-2 vaccines in autoimmune diseases. Descriptive analysis and a binary logistic regression model, to evaluate predictors of COVID-19-related hospitalization, were performed. P-value < 0.05 was significant. The included 160 patients were predominantly females (83.1%), with mean (SD) age 40.23 (13.19) years. Patients received 2 (19%), 3 (70%) or 4 (11%) vaccine doses. The initial two-dose series was mainly with ChAdOx1 (Oxford/AstraZeneca) (58%) or BBIBP-CorV (Sinopharm-Beijing) (34%). The first booster (n=150) was with BNT162b2 (BioNtech/Fosun Pharma/Pfizer) (63%) or ChAdOx1 (29%). The second booster (n=112) was with BNT162b2 (40%) or ChAdOx1 (26%). COVID-19 hospitalization rate was 17.5%. IMRD moderate/high activity (OR: 5.84, CI: 1.9-18.5, p=0.002) and treatment with corticosteroids (OR: 2.94, CI: 1.02-8.49, p=0.0043) associated with higher odds of hospitalization, while the increasing number of vaccine doses was protective (OR: 0.37, CI: 0.15-0.9, p=0.032). These findings, along with previous reassuring results about the safety of the COVID-19 vaccines, argue in favour of booster vaccination in IMRD patients.