Effects of SARS-CoV-2 Virus on Thyroid Function: A Narrative Review

SARS-CoV-2 is a type of coronavirus that causes COVID-19 disease. The virus can infect various organs by triggering hormones, regulatory and messenger molecules, and immune-inflammatory responses. Given the vital role of thyroid in metabolism, it is important to understand the potential effects of SARS-CoV-2 on the thyroid gland. In this article, reports and studies examining the effects of SARS-CoV-2 infection on thyroid are reviewed, and possible effects of this virus on thyroid function are discussed. According to the available evidence, SARS-CoV-2 can adversely impact thyroid function directly by affecting the pituitary-thyroid axis or indirectly by triggering immune-inflammatory responses. COVID-19-dependent thyroid disorders have been biochemically observed in three forms: hypothyroidism, thyrotoxicosis, and nonthyroidal illness syndrome. Subacute thyroiditis has been one of the most common clinical conditions of SARS-CoV-2-dependent thyrotoxicosis. In addition, SARS-CoV-2 may cause recurrence of improved thyroid diseases or exacerbate current diseases. There is no evidence that thyroid disease, including thyroid cancer, increases the risk of COVID-19 or exacerbates its complications. According to current studies, COVID-19 medications, including glucocorticoids and anticoagulants, have no adverse effects on thyroid function in non-acute COVID-19 patients. Further studies are needed to investigate the interactions between SARS-CoV-2 infection and thyroid function.