Autoimmune diseases in the era of COVID-19: emerging mechanisms, clinical implications, vaccine considerations, and future directions.

The coronavirus disease 2019 (COVID-19) pandemic has highlighted a complex, bidirectional relationship between SARSCoV-2 infection and autoimmune diseases. This review examines how SARS-CoV-2 infection influences the incidence, progression, and outcomes of five major autoimmune conditions: systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease, and Guillain-Barré syndrome. Patients with autoimmune diseases are at increased risk of severe COVID-19 due to intrinsic immune dysregulation and the use of immunosuppressive therapies, both of which impair antiviral host defenses. Conversely, COVID-19 has been implicated in the initiation and exacerbation of autoimmune responses through mechanisms such as molecular mimicry and bystander activation. Concerns have also arisen regarding the safety and efficacy of COVID-19 vaccines in immunocompromised populations. Although vaccines are generally tolerated in these individuals, certain immunosuppressive therapies may attenuate humoral and cellular immune responses. Strategies such as adjusting immunosuppressive regimens and optimizing the timing of vaccination have been proposed to improve vaccine efficacy. Disease-specific considerations are essential to balance infection risk with adequate control of autoimmune activity. Overall, this review underscores the importance of individualized treatment strategies, close clinical monitoring, and interdisciplinary care in managing patients with autoimmune diseases during the COVID-19 pandemic. A deeper understanding of these interactions will be critical for improving patient outcomes and preparing for future pandemics involving immune-mediated diseases.