SARS-CoV-2 vaccine may trigger thyroid autoimmunity: real-life experience and review of the literature

PURPOSE: SARS-CoV-2 infection can be associated with destructive thyroiditis and triggers thyroid autoimmunity. More recent evidence suggests that SARS-CoV-2 vaccines may also be associated with permanent or transient thyroid dysfunction in susceptible individuals. METHODS: We observed three patients who developed/exacerbated autoimmune thyroid diseases (AITDs) shortly after receiving mRNA-based vaccines against SARS-CoV2. Clinical histories are reported, and relevant literature in the field is summarized. RESULTS: Our case series gives a description of the full spectrum of autoimmune disorders that may occur after SARS-CoV-2 vaccines administration, ranging from a case of new-onset Graves’ disease to autoimmune hypothyroidism in two patients with pre-existing AITDs. Our three patients had a personal and/or family history of autoimmune disorders, suggesting that genetic predisposition is an important risk factor for the development of AITDs following vaccination. Moreover, our real-life experience demonstrates that persistent hypothyroidism may occur in the long run and should be overlooked; subjects with a previous AITDs are at risk of developing it. Reviewing the pertinent literature up to date Graves’ disease is the most common vaccine-related AITDs with up to 51 cases reported in the literature, occurring mainly in female patients with no personal history of AIDTs, while only a case of autoimmune hypothyroidism has been reported so far. CONCLUSIONS: SARS-CoV-2 vaccines can trigger autoimmune reactions and the present case series contributes to make clinicians aware of full spectrum of AITDs that may occur following vaccination. Thyroid function monitoring is recommended, mainly in subjects with a personal/family history of AITDs.