thyroid function in the time of covid-19: a systematic review of disease progression and vaccination effect

Objectives: this systematic review sought to address three key questions: (1) what differences in abnormal thyroid function test results are observed between covid-19 patients and healthy individuals? (2) how does the severity of covid-19 infection influence the development of thyroid dysfunction? (3) what impact do covid-19 vaccines have on thyroid function and autoimmune processes? methods: a literature search was conducted in pubmed, web of science, and scopus from december 2019 to april 2023 to identify studies on thyroid dysfunction in covid-19 patients without pre-existing thyroid conditions. the search focused on observational and case-control studies. results: the literature search yielded 329 reports, from which duplicates and unrelated publications were excluded. ultimately, 21 studies met the inclusion criteria and were selected for review. a second literature search yielded 605 reports, from which 5 studies were selected for inclusion in the systematic review. conclusions: the findings suggest that sars-cov-2 infection can induce transient and reversible thyroid dysfunction, possibly through direct viral effects on the thyroid gland or via indirect immune-mediated mechanisms. clinicians should be mindful of the potential, albeit rare, thyroid-related adverse effects of covid-19 vaccines and monitor thyroid function, particularly in high-risk individuals.