Sars-Cov-2 Vaccine Associated Graves' Disease

ABSTRACT

The effect of SARS-CoV-2 vaccine on the thyroid is not well understood. There are increasing reports of varying effects of the vaccine on the thyroid with the most common presentation being subacute thyroiditis. Rarely, Graves' disease following SARS-CoV- 2 has been observed. We present two cases of the development of Graves' disease after SARS-CoV-2 vaccination. A 37-year-old male presented to the office with weight loss, palpitations, tremors, diarrhea, and insomnia within a month of receiving the third dose of the SARS-CoV-2 vaccine. On physical exam he had bilateral periorbital edema. His TSH was <0.005 uIU/mL, free T4 21 ng/dl, total T3 651 ng/dl, and thyroid stimulating immunoglobulin (TSI) was positive, consistent with Graves' disease. He was started on methimazole and propranolol with improvement in thyroid function tests and symptoms noted. Similarly, a 56-year-old female presented to the office with weight loss, tremors, palpitations, and insomnia that began a few weeks after the third dose of the SARS-CoV-2 vaccine. Her TSH was <0.005 uIU/mL, free T4 > 7.77 ng/dl, total T3 > 651 ng/dl, and TSI was positive. She was initiated on methimazole but due to development of ageusia, she was trialed on propylthiouracil. She failed biochemical response to propylthiouracil, and thus was transitioned back to methimazole with subsequent improvement in thyroid function tests and symptoms. Notably, both patients were previously clinically and biochemically euthyroid. Neither patient had predisposing risk factors, such as personal or family history of autoimmune diseases, personal or family history of Graves' disease/thyroid dysfunction, preceding infection, contrast exposure, or amiodarone use. There are only five documented cases of Graves' disease after the SARS-CoV-2 vaccine. These two additional cases add to the emerging evidence of an association between Graves' disease and the SARS-CoV-2 vaccine, particularly after the third dose. One proposed mechanism is that the mRNA vaccine acts as an adjuvant, triggering an autoimmune response in genetically susceptible individuals. Please note that association does not mean causation. More studies are needed to further investigate the relationship between the thyroid and SARS-CoV-2 vaccine. It is essential for healthcare providers to identify Graves' disease following the SARS-CoV-2 vaccine even in patients with no risk factors and promptly initiate treatment to prevent hyperthyroid complications.