Abstract
Background: The 2020-2023 COVID-19 pandemic saw an unprecedented global vaccination campaign to inoculate billions of people against the SARS-CoV-2 virus with priority for vulnerable populations including patients with compromised immune systems and autoimmune disorders. Public health mass vaccination campaigns proceeded with newly and rapidly developed vaccines, including novel mRNA vaccines, viral vector vaccines, inactivated viral vaccines, and protein subunit vaccines. As a result, significant evidence for various mechanisms of action of COVID-19 vaccination in autoimmunity have emerged along with concerns about how potential iatrogenic events should be properly reported in the literature.
Objective and Methods: This study presents a focused analysis of evidence identified in a scoping review on published clinical reports of autoimmune patients receiving COVID-19 vaccination. Here we present a detailed summary of one of the prespecified components not previously addressed: proposed mechanisms of action of the COVID-19 vaccines for autoimmune symptoms, such as flares or relapses or new disorders, for some of the most common autoimmune diseases including Graves’ disease, Hashimoto’s thyroiditis, multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, and type 1 diabetes mellitus.
Findings: Mechanisms of action proposed in the clinical reports were diverse and detailed including the following: immune priming, pathways related to antigen delivery systems, autoimmune/inflammatory syndrome induced by adjuvants, interactions with immunosuppressive and disease modifying therapies, bystander immune activation, molecular mimicry, polyclonal activation, epitope spreading, genetic vulnerability, shifting imbalance in endocrine systems, cross-reactive immunity, nonspecific immunity “boosting”, and immune system dysregulation. Several issues with supporting evidence, inconsistencies, and contradictions between study findings and clinical recommendations are also presented.
Conclusions: Future research should aim to distinguish causal from coincidental associations for adverse events and vaccinations recommendations should be based on quality cost-benefit analyses.