Nikhil Prasad Fact checked by:Thailand Medical News Team May 19, 2025 17 hours, 55 minutes ago
Medical News: COVID-19’s Hidden Damage to the Thyroid Gland
While most people associate COVID-19 with symptoms like cough, fever, or fatigue, there is now growing evidence that the virus can also damage a small but vital organ in the neck — the thyroid gland. A major new review of medical studies has uncovered a strong connection between SARS-CoV-2, the virus that causes COVID-19, and multiple forms of thyroid dysfunction. These problems can persist even after the initial infection has passed and may contribute to ongoing symptoms experienced in long COVID.
COVID-19 Infections May Be Causing Widespread Thyroid Issues Around the World
This
Medical News report is based on a comprehensive review by researchers from several institutions, including the Department of Clinical Medicine at St Matthew’s University School of Medicine in Grand Cayman, the University of Kentucky, Appalachian Regional Healthcare in Kentucky, and the American University of Antigua. The study was led by Dr. Kamyar Asadipooya of the Barnstable Brown Diabetes and Obesity Center at the University of Kentucky. Their findings paint a concerning picture of how the pandemic may be quietly driving a rise in thyroid problems globally.
COVID-19 and the Thyroid Gland
The thyroid gland is responsible for regulating metabolism and energy through hormones like T3 and T4. When this gland becomes overactive or underactive, it can lead to significant health problems such as weight gain, fatigue, heart palpitations, anxiety, or depression. The study revealed that SARS-CoV-2 can enter thyroid cells using a receptor called ACE2, which is found on the surface of thyroid tissue. Once inside, the virus may disrupt normal thyroid function either by direct viral damage or by triggering the body’s immune system to attack the gland.
One of the earliest signs of thyroid involvement was documented in May 2020, when doctors identified a case of subacute thyroiditis — an inflammation of the thyroid — following a mild COVID-19 infection. Since then, numerous cases have confirmed that COVID-19 can lead to various thyroid disorders, including hypothyroidism (underactive thyroid), hyperthyroidism (overactive thyroid), and even autoimmune conditions like Graves’ disease and Hashimoto’s thyroiditis.
What the Global Data Shows
The review examined 32 high-quality studies conducted in countries including Italy, China, India, South Korea, Bangladesh, the United States, and the United Kingdom. The evidence pointed to a clear pattern — thyroid problems were significantly more common in people who had been infected with SARS-CoV-2. In one large systematic review covering over 9,700 COVID-19 patients, about 15% had some form of thyroid dysfunction. More severe cases of COVID-19 were even more likely to have thyroid issues, with rates as high as 21%.
The most common problem identified was non-thyroidal illness syndrome (NTIS), also known as low T3 syndrome or sick euthyroid syndrome. This condition involves a drop in the
levels of the thyroid hormone T3, and it was found in up to 58% of COVID-19 patients in some regions. Other disorders included subacute thyroiditis, autoimmune thyroiditis, and painless thyroiditis, all of which could result in long-term thyroid imbalances.
Importantly, some of these thyroid issues were temporary and resolved after recovery from COVID-19, while others led to lasting conditions requiring medical treatment. Women and older adults, especially those over the age of 65, were more likely to develop serious or persistent thyroid dysfunction.
Graves’ Disease and COVID-19
One particularly alarming finding was the increased incidence of Graves’ disease, an autoimmune form of hyperthyroidism. Researchers noted a spike in new Graves’ disease cases during the pandemic, especially in women who had a prior history of smoking. In Spain, for instance, the incidence of Graves’ disease noticeably increased during 2020 and 2021. Similar trends were reported in the United States, where pediatric cases of Graves’ disease also rose sharply in the first two years of the pandemic.
Can Thyroid Dysfunction Lead to Long COVID?
The symptoms of thyroid dysfunction — fatigue, brain fog, weight changes, and depression — overlap with those of long COVID. This has led many researchers to believe there could be a connection. While some studies support this theory, others have found no clear relationship between long COVID and thyroid disorders. Still, the potential for subtle thyroid damage contributing to prolonged symptoms cannot be dismissed, and the authors urge doctors to consider thyroid testing in patients struggling with post-COVID complications.
Could COVID Trigger Autoimmune Thyroid Diseases?
One of the more unsettling aspects of the findings was how COVID-19 appeared to increase the risk of autoimmune thyroid diseases. The virus seems capable of activating the immune system in such a way that it begins to attack the body’s own tissues, including the thyroid gland. This was supported by studies from Hungary, Bulgaria, Italy, and Colombia, which documented rises in autoimmune thyroiditis in both children and adults who had recovered from COVID-19. In some cases, anti-thyroid antibodies were found at significantly higher levels in people who had previously been infected with the virus.
Rethinking COVID-19 Treatments to Protect the Thyroid
Given these alarming trends, the researchers believe that the standard COVID-19 treatments — especially antivirals — may not be enough. SARS-CoV-2 is constantly mutating, which makes it more difficult to control with drugs that target specific viral genes. As a result, they propose adding commonly available medications that can reduce the virus’s ability to infect cells and calm the immune response.
They recommend combining drugs such as dipeptidyl peptidase 4 (DPP-4) inhibitors, spironolactone, metformin, and ursodeoxycholic acid (UDCA). These medications can reduce inflammation, block viral entry into cells, and help prevent immune system overreaction. In one clinical trial, the combination of spironolactone and a DPP-4 inhibitor lowered the rate of hospitalization by nearly 78% — outperforming some antivirals. These medications are also less likely to promote viral mutations, making them promising tools in the fight against COVID-19 and its complications.
A Warning and a Call for More Research
Although many people think the COVID-19 crisis is over, this study shows that the virus’s effects are still unfolding — especially in terms of its impact on the endocrine system. The thyroid gland is just one of several organs that may continue to suffer long after the infection has cleared. More clinical trials are urgently needed to test safer and broader-acting medications. Routine screening of thyroid function in COVID-19 patients — especially those with lingering symptoms — could help catch these problems early and reduce long-term health burdens.
Conclusion
This extensive review sheds light on the often-overlooked connection between COVID-19 and thyroid dysfunction. From temporary hormone imbalances to permanent autoimmune conditions, the effects of the virus on the thyroid are real and widespread. The global data suggests that millions of people may have experienced or may still be at risk of developing thyroid-related health issues due to SARS-CoV-2. As such, greater awareness among doctors, policymakers, and the public is needed. Routine thyroid testing in both acute and post-COVID cases, especially in vulnerable groups such as the elderly and women, could significantly improve health outcomes. Most importantly, this study underscores the importance of moving beyond antiviral-only treatment strategies and adopting broader approaches that reduce inflammation, immune overactivation, and viral entry. The pandemic may have subsided in visibility, but its long tail continues to affect human health in profound and unexpected ways.
The study findings were published in the peer reviewed journal: Frontiers in Endocrinology
https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2025.1535169/full
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