Background: Subacute thyroiditis is an inflammatory disease associated with vaccinations. There have been reports of subacute painful thyroiditis following SARS-CoV-2 vaccination. However, only a few cases of painless thyroiditis have been reported and mostly were after mRNA vaccine. The authors presented a case of painless thyroiditis after viral vector SARS-CoV-2 vaccine.

Case Report: A 60-year-old woman, who had no prior history of thyroid disease, presented with atrial fibrillation and no enlarged thyroid gland or neck pain. She had received ChAdOx1 nCoV-19 vaccine from AstraZeneca two weeks prior to the onset of symptoms. Her blood tests revealed primary thyrotoxicosis, and thyroid uptake confirmed thyroiditis.

Discussion: Vaccine-induced thyroiditis has been reported in viral vaccines. The pathophysiology of SARS-CoV-2 vaccine-induced thyroiditis is still unknown. It is possible that the immune response to the SARS-CoV-2 vaccine will also cross-react and cause thyroiditis.

Conclusion: It is possible that SARS-CoV-2 vaccine can cause painless thyroiditis.

Keywords: Covid-19; SARS-CoV-2; Thyroiditis; Vaccine

DOI: 10.35755/jmedassocthai.2022.12.13721

Received 28 February 2022 | Revised 1 November 2022 | Accepted 7 November 2022