Re: "Thyroid Eye Disease Following COVID-19 Vaccine in a Patient With a History Graves' Disease: A Case Report".

To the Editor:

We would like to share ideas on the publication “Thyroid Eye Disease Following COVID-19 Vaccine in a Patient With a History Graves’ Disease: A Case Report.”[1] Rubinstein noted that “the temporal relationship to her vaccination was likely consistent with autoimmune/inflammatory syndrome associated with adjuvants.[1]” Abnormal thyroid is a possible problem following the coronavirus disease 2019 (COVID-19) vaccination. A clear pathogenesis of the problem is still not conclusive. In many reports, there is no history of prevaccination thyroid status of the patient. In the present report by Rubinstein, it is clear that the patient is a known case of Graves’ disease, and vaccination might be an aggravating factor. Nevertheless, there are no data on abnormal antibody induced by vaccine in this case. It is usually a question whether an exacerbation after the COVID-19 vaccination is a coincidence or not.[2] Abnormal thyroid function might be laboratory interference[3] or an actual pathology. An effect of adjuvant, as proposed by Rubinstein,[1] might be a pathophysiological process. Also, the increased blood viscosity induced by vaccination is also another possible pathophysiological process.[4] Vaccine can induce significant increase in blood viscosity level,[4] and a very high blood viscosity is associated with exophthalmos at a stable stage of hyperthyroidism.[5]