Clinical Thyroidology® for the Public

Summaries for the Public from recent articles in Clinical Thyroidology
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COVID-19 AND THE THYROID
Early-onset Graves’ disease after COVID-19 vaccination responds rapidly to low-dose methimazole

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BACKGROUND
COVID-19 infection has been associated with the development of several endocrine problems including different forms of thyroiditis and Graves’ disease. The likely reasons for this include the virus directly attaching thyroid cells and the increase in activation of the immune system and increasing antibodies during and after COVID-19 infection. This is because both hyperthyroidism and hypothyroidism are usually caused by antibodies attacking the thyroid.

Vaccination against COVID-19 has been a worldwide effort and has been closely monitored. There have been some case reports of the development of autoimmune thyroid problems following COVID-19 vaccination. This study examined the characterization of Graves’ disease occurring after COVID-19 vaccination

THE FULL ARTICLE TITLE
 di Filippo L et al 2022 Distinct clinical features of post- COVID-19 vaccination early-onset Graves’ disease (PoVEO GD). J Clin Endocrinol Metab. Epub 2022 Sep 21. PMID: 36130234.

SUMMARY OF THE STUDY
This study included adult patients who received vaccination against COVID-19 and were followed at an endocrine referral center for a new diagnosis of Graves’ disease between January 1, 2021, and December 31, 2021. The study group was divided between the timing of presentation with hyperthyroidism—either early (within 4 weeks postvaccination), between weeks 4 and 8, or late (>8 weeks postvaccination).

Based on the analysis of 64 patients exposed to at least one immunization dose against COVID-19, either with the Pfizer (63.9%), Moderna (21.3%), or Astra Zeneca (14.8%) vaccine, the authors found that Graves’ disease pre-existed in 35 patients (55%) and developed after the vaccination in 29 patients (45%). Among the latter group, 20 patients presented with Graves’ disease within 4 weeks after vaccination, and their symptoms developed as early as 9 days after immunization, while in 9 patients Graves’ disease occurred later—more than 8 weeks after exposure. Those with early-onset post-COVID vaccination Graves’ disease were characterized by an older age at presentation (average 51 years vs. 35 years) and a higher occurrence in men (40% vs. 13.6%) than in those with preexisting and late-onset Graves’ disease after vaccination. Moreover, patients with early-onset post-COVID vaccination Graves’ disease were characterized by a quicker response to Methimazole after 3 months of follow-up than those with preexisting and late-onset Graves’ disease after vaccination.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
Early-onset post-COVID vaccination Graves’ disease is characterized by unique clinical features, including an older age at presentation, a higher occurrence in men, and a faster recovery to normal thyroid levels, as compared with those with preexisting and late-onset Graves’ disease after vaccination. The latter observation suggests a potentially self-limiting nature of the early-onset autoimmunity after exposure to COVID-19 vaccines.

— Alan P. Farwell, MD

ABBREVIATIONS & DEFINITIONS

Graves’ disease: the most common cause of hyperthyroidism in the United States. It is caused by antibodies that attack the thyroid and turn it on.

Hyperthyroidism: a condition where the thyroid gland is overactive and produces too much thyroid hormone. Hyperthyroidism may be treated with antithyroid meds (Methimazole, Propylthiouracil), radioactive iodine or surgery.

Thyroiditis: inflammation of the thyroid, most commonly cause by antibodies that attack the thyroid as seen in Hashimoto’s thyroiditis and post-partum thyroiditis. It can also result from an infection in the thyroid.

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