Characteristics of emerging new autoimmune diseases after COVID-19 vaccination: A sub-study by the COVAD group

Background: Despite the overall safety and efficacy of COVID-19 vaccinations, rare cases of systemic autoimmune diseases (SAIDs) have been reported post-vaccination. This study used a global survey to analyze SAIDs in susceptible individuals’ post-vaccination.
Methods: A cross-sectional study was conducted among participants with self-reported new-onset SAIDs using the COVID-19 Vaccination in Autoimmune Diseases (COVAD) 2 study dataset- a validated, patient-reported e-survey, to analyze the long-term safety of COVID-19 vaccines. Baseline characteristics of patients with new-onset SAIDs and vaccinated healthy controls (HCs) were compared after propensity score matching based on age and sex in a 1:4 ratio.
Results: Of 16750 individuals, 74 (median age 52 years, 79.9% females, and 76.7% Caucasians) had new-onset SAID, post-vaccination, mainly idiopathic inflammatory myopathies (IIMs) (n=23, 31.51%), arthritis (n=15; 20.53%) and polymyalgia rheumatica (PMR) (n=12, 16.40%). Higher odds of new-onset SAIDs were noted among Caucasians (OR=5.3; 95%CI=2.9-9.7; P<0.001) and Moderna vaccine recipients (OR=2.7; 95%CI=1.3-5.3; P=0.004). New-onset SAIDs were associated with AID multimorbidity (OR=1.4; 95%CI=1.1-1.7; P<0.001), mental health disorders (OR=1.6; 95%CI=1.3-1.9; P<0.001), and mixed race (OR=2.2; 95%CI=1.2-4.2; P=0.010) where those aged >60 years (OR=0.6; 95%IC=0.4-0.8; P=0.007) and from high/medium human development index (HDI) countries (compared to very high HDI) reported fewer events than HCs.
Conclusion: This study reports a low occurrence of new-onset SAIDs following COVID-19 vaccination, primarily IIMs, PMR and inflammatory arthritis. Identified risk factors included pre-existing AID multimorbidity, mental health diseases, and mixed race. Re-vaccination was well tolerated is most patients therefore, we recommend continuing COVID-19 vaccination in the general population. However, long-term studies are needed to understand the autoimmune phenomena arising post-vaccination.