Endocrine Abstracts

A 50 year old Asian lady developed neck pain and sore throat 10 days after first dose of AstraZeneca COVID-19 vaccination. Her dentist thought she had tonsillitis. She then presented to hospital a few days later with dyspnoea, palpitations, tremor and neck pain. She was apyrexial but clinically thyrotoxic with sinus tachycardia. Thyroid gland had normal size with tenderness without bruit or lymphadenopathy. Her Free T4 was >100 pmol/l (11.2 - 20.2), TSH < 0.01mIU/l, ESR: 58 mm/hr (0-30 mm/hr) and CRP: 23 mg/l (0-4.9 mg/l), with normal full blood count. Thyroid peroxidase antibodies were 32 IU/ml (0-50 IU/ml) and TSH receptor Antibodies was 1.7 IU/l (0-2.9). Thyroid Ultrasound scan 3 weeks later showed subtle heterogeneity and hypoechogenicity with appearance suggesting thyroiditis. Thyroid uptake five weeks after presentation showed relatively reduced tracer uptake in upper left lobe with thyroid to background ratio 2.4 (0.5-3.5) . There was no previous medical history, recent viral infections, family history of thyroid or autoimmune conditions, allergies. She was not on any medication and was not pregnant. She was started on Carbimazole which was stopped 12 days later (T4: 35.6 pmol/l). She was asymptomatic a week later.

Discussion: This is the first reported case of AstraZeneca COVID-19 vaccine induced thyroiditis. It is of public and medical importance that we present any cases of such side effects as this will keep clinicians aware of this. There has been 7 cases of vaccine induced thyroiditis in literature of which only one is due to COVID-19 vaccine (Pfizer). Proposed mechanisms include T -cell mediated vaccine antigen presentation or autoimmune /inflammatory syndrome induced by adjuvants. This also raises the question if giving the 2nd vaccination is appropriate in this patient.

Conclusion: COVID-19 AstraZeneca induced subacute thyroiditis had a rapid recovery but long term sequelae and development of post-thyroiditis hypothyroidism is still unknown.