Abstract
SARS-CoV-2 virus responsible for acute respiratory disease affected other organs leading to co-existence symptoms or complications. Thyroid gland was one of them due to expression of angiotensin-converting enzyme 2 (ACE2), the protein facilitating viral binding to the host cells. Moreover, thyroid gland, important for regulation of hormonal network, is extremely sensitive to any changes in homeostasis and metabolism. It was shown, that COVID-19 was associated with induction of thyroid disease or increasing existing functional disturbances or autoimmune process. Thyroid diseases are mainly based on immunological pathomechanism although the relation between immune system and thyroid function is bidirectional e.g. thyroid hormones modulate specific immune responses, including cell-mediated immunity, NK cell activity, the production of antiviral interferon (IFN) and proliferation of T- and B-lymphocytes. The effects of COVID-19 and mRNA vaccine on thyroid function and diseases are discussed.