Subacute thyroiditis after the third dose of the COVID-19 mRNA vaccine. Case report.

Subacute thyroiditis (SAT) is a thyroid inflammatory disease, whose pathogenesis is still unclear. We report a 52-year-old female with SAT after the third dose of COVID-19 mRNA vaccine BNT162b2 (Pfizer-BioNTech). This case was documented with laboratory tests and ultrasound examination. She needed therapy during the acute phase and subsequently thyroxine supplementation.