Risk of autoimmune skin and connective tissue disorders after mRNA-based COVID-19 vaccination

Background: Data on the association between the development of autoimmune diseases and COVID-19 vaccination are limited.Objective: To investigate the incidence and risk of autoimmune connective tissue disorders following mRNA-based COVID-19 vaccination.Methods: This nationwide population-based study was conducted in South Korea. Individuals who received vaccination between September 8, 2020-December 31, 2021, were identified. Historical prepandemic controls were matched for age and sex in 1:1 ratio. The incidence rate and risk of disease outcomes were compared.Results: A total of 3,838,120 vaccinated individuals and 3,834,804 controls without evidence of COVID-19 were included. The risk of alopecia areata, alopecia totalis, primary cicatricial alopecia, psoriasis, vitiligo, anti-neutrophil cytoplasmic antibody-associated vasculitis, sarcoidosis, Behcet disease, Crohn disease, ulcerative colitis, rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, Sjogren syndrome, ankylosing spondylitis, dermato/polymyositis, and bullous pemphigoid was not significantly higher in vaccinated individuals than in controls. The risk was comparable according to age, sex, type of mRNAbased vaccine, and cross-vaccination status.Limitations: Possible selection bias and residual confounders.Conclusion: These findings suggest that most autoimmune connective tissue disorders are not associated with a significant increase in risk. However, caution is necessary when interpreting results for rare outcomes due to limited statistical power.

Automated summary

This nationwide population-based study conducted in South Korea investigated the incidence and risk of autoimmune connective tissue disorders following mRNA-based COVID-19 vaccination. The results suggest that the risk of most autoimmune connective tissue disorders is not significantly increased in vaccinated individuals compared to controls. However, caution is necessary when interpreting the results for rare outcomes.