Thyroid Diseases Linked to COVID-19 Vaccination: Studies

Thyroid disorders, especially hypothyroidism, may be linked to COVID-19 vaccinations as possible adverse reactions, reports a recent Indian study.

The study authors from Banaras Hindu University identified 75 cases of thyroid disturbance after COVID-19 vaccinations. Patients who took vaccinations after recovery from COVID-19 had an added risk of post-vaccine adverse reactions and the persistence of such reactions.

While the study only investigated vector-based vaccines of AstraZeneca and Indian biotech company Bharat Biotech’s Covaxin, neither of which are available in the United States, isolated cases of thyroiditis “exist in the early period of COVID-19 vaccinations, largely after mRNA vaccines,” the authors wrote in the study abstract.

Internist and functional medicine practitioner Dr. Yusuf Saleeby of Carolina Holistic Medicine said that he would expect similar reactions from both vector-based and mRNA-based COVID-19 vaccines since both induce the body to produce the virus’ spike proteins.

“I see hypothyroidism 90 percent of the time” for patients with thyroid problems post-vaccination, Dr. Saleeby said. Some people first present with signs of hyperthyroidism and later develop hypothyroidism.

Dr. Saleeby reasoned that spike protein could disturb the normal feedback loop mechanism between the thyroid and other endocrine organs, disrupting hormonal production.

A May 2020 study showed that antibodies formed against the spike protein can bind strongly to thyroid proteins, possibly inducing autoimmune thyroid damage. A subsequent 2021 study found that human antibodies formed against the spike protein can react with thyroid tissues.

Hypothyroidism vs. Hyperthyroidism

Hypothyroidism refers to when the thyroid is not making enough hormones.

It usually occurs as part of an autoimmune disease, where the body attacks its own thyroid.

Since thyroid hormones are responsible for metabolism, meaning the breaking down of energy, hypothyroidism is usually associated with symptoms of decreased or insufficient metabolism, like weight gain and slow heart rate.

Hyperthyroid is the opposite scenario; the thyroid makes hormones in excess, so it is usually associated with signs of increased metabolism or hypermetabolism, such as weight loss and accelerated heart rate.

Both conditions share various symptoms, including enlarged thyroid, fatigue, hair loss, and sexual dysfunctions.

New-Onset Hypothyroidism

Study participants were followed from 2022 to 2023. Over half had a preexisting thyroid dysfunction, most of which were hypothyroidism.

“Flares were common ... after the 2nd dose of COVID-19 vaccine,” the authors wrote, adding that they tended to appear at around five, 28, and 13 weeks after the first, second, and booster dose, respectively.

Patients who took the vaccine after recovering from a COVID-19 infection were likelier to report persistent health problems.

New-onset hypothyroidism was particularly prominent, accounting for about one-third of the cases, mostly among females. Over 77 percent of the cases occurred after the second dose, and the median onset time was the fourth month.

Commonly reported symptoms of hypothyroidism included body swelling, menstrual abnormalities, weight gain, and fatigue.

A few cases of hyperthyroidism were also reported.

Thyroid Disturbances and COVID mRNA Vaccines

Studies so far have not provided a precise estimate of the rate of thyroid disturbance post-COVID-19 vaccination, and not all thyroid disturbance reports are conclusively linked to the COVID-19 vaccines.

Yet some studies have been published investigating the effects of COVID-19 mRNA vaccines on the thyroid.

The most common links reported have been subacute thyroiditis, meaning thyroid inflammation, and Graves’ disease, an autoimmune disease that can lead to hyperthyroidism.

Multiple studies have documented subacute thyroiditis days after mRNA vaccination.

One Japanese study published in May 2023 identified Graves’ disease three weeks after mRNA COVID-19 vaccination.

The patient arrived at the emergency room a week after receiving his second mRNA COVID vaccine. The study authors suspected post-vaccine myocarditis, but the patient showed no signs of it.

Two weeks later, he presented with weight loss, palpitations, and hand tremors. After being tested for thyroid hormones, he was diagnosed with Graves’ disease.

A year later, the patient’s thyroid hormones had not returned to normal, and he remained on medication.

Another Japanese study published in January followed 70 health care workers after their second and third doses of the COVID-19 vaccines.

After the third dose, there was a statistically significant increase in TgAb, an antibody formed against a thyroid protein. This protein is associated with Graves’ disease.

“Increase in TgAb was associated with history of … thyroid diseases,” the study authors wrote.

Other hypothyroid diseases following COVID vaccination have also been reported in several case studies.

An American study reported the case of a healthy 50-year-old woman who was diagnosed with overt hypothyroidism three weeks after administration of the Pfizer vaccine. She had “a weight gain of seven pounds in six weeks since the first dose,” the authors reported.

A Taiwan study also reported a coincidental Hashimoto’s disease—a hypothyroid condition—a month after COVID-19 mRNA vaccination (pdf).

Conflicting Evidence

Other studies have concluded that COVID-19 vaccinations are not associated with hyperthyroidism and Graves’ disease.

An Israeli study published in October matched more than 700 Graves’ disease patients with over 1,400 healthy people and compared them for Graves’ disease incidence. The authors found that when comparing people who received at least one dose of the COVID-19 vaccine, there was no significant link.

Yet it should be noted that health practitioners tend to find an increased risk of adverse reactions with repeated doses.

“I do see more thyroid disruption the more a patient either gets sick with COVID-19 infections and/or the more they get vaccinated,” Dr. Saleeby said. “Cannot quantify which is worse. But the number of ‘infections’ or ‘injections’ they get, the worse off they are.”

Reposted from: https://www.theepochtimes.com/health/thyroid-diseases-linked-to-covid-19-vaccination-studies-5540520