Abstract
BACKGROUND: Subacute thyroiditis, an inflammatory disease, has been reported caused by vaccines in rare cases. In the context of the coronavirus disease 19 pandemic, various SARS-CoV-2 vaccines have been developed and may be potential triggers for subacute thyroiditis. CASE PRESENTATION: We report a case of subacute thyroiditis 3 days after receiving the second dose of inactivated SARS-CoV-2 vaccine (BBIBP-CorV). The patient did not report a previous history of thyroid disease, upper respiratory tract infection, or COVID-19. Physical examination, laboratory testing, ultrasonography, and radioactive iodine uptake were consistent with subacute thyroiditis. During follow-up, the patient recovered from symptoms and signs, and imaging changes except for hypothyroidism, requiring an ongoing thyroxine replacement. CONCLUSIONS: Inactivated SARS-CoV-2 vaccine may be a causal trigger leading to subacute thyroiditis. Clinicians should be aware of subacute thyroiditis as a possible thyroid-related side effect of an inactivated SARS-CoV-2 vaccine.