Differences in Clinical Aspects Between Subacute Thyroiditis Associated with COVID-19 Vaccines and Classical Subacute...

Area of Science:

• Endocrinology
• Immunology
• Vaccinology

Background:

• Subacute thyroiditis (SAT) following SARS-CoV-2 vaccination is understudied.
• Understanding clinical differences between vaccine-associated SAT (Vac-SAT) and classical SAT is crucial.

Purpose of the Study:

• To compare clinical characteristics of SAT developed after COVID-19 vaccination (Vac-SAT) versus classical SAT.
• To investigate potential associations between specific COVID-19 vaccines (CoronaVac, Pfizer/BioNTech) and SAT development.

Main Methods:

• Retrospective study comparing 23 Vac-SAT patients with 62 Classical-SAT patients.
• Exclusion criteria included prior SARS-CoV-2 infection or other vaccinations.
• Clinical data including SAT duration and post-resolution thyroid-stimulating hormone (TSH) levels were analyzed.

Main Results:

• Vac-SAT duration was significantly longer than Classical-SAT (p=0.023).
• Previous levothyroxine (LT4) use and elevated TSH after resolution were more frequent in Vac-SAT (p=0.027, p=0.041).
• SAT onset after the first vaccine dose was infrequent for both CoronaVac and BioNTech vaccines.

Conclusions:

• While a definitive causal link remains unproven, Vac-SAT exhibits distinct clinical features.
• Longer SAT duration and post-resolution TSH elevation in Vac-SAT warrant close thyroid function monitoring.
• Further research is needed to elucidate the relationship between COVID-19 vaccines and SAT.