Endocrine Abstracts

Introduction: Covid-19 vaccination have been introduced to reduce overall severity and mortality of COVID-19 infection. Autoimmune/inflammatory syndrome induced by adjuvants (ASIA) is a syndrome first described in 2011 that triggers autoimmune conditions after exposure to various adjuvants through various mechanisms. We report three cases of autoimmune thyrotoxicosis post mRNA type vaccine for COVID-19 possibly linked to adjuvants present in the vaccine.

Case 1: A 34-year-old patient was newly diagnosed with Grave’s disease, within 1 month after her SARS-CoV-2 vaccine (Pfizer-BioNTech) when she presented with symptoms of palpitations, heat intolerance and a painless neck swelling. Physical examination revealed fine tremors with a diffuse goiter. Results of biochemical workup was as follows: TSH (Thyroid stimulating hormone): <0.008 mIU/l (low), FT4(free thyroxine): 123.1 pmol/l (elevated), FT3(free triiodothyronine): 9.10 pmol/l (elevated), anti-TPO (antithyroid peroxidase) : 9.51 IU/ml (normal), anti TG (antithyroglobulin): 11.04 IU/ml (normal), TSHrAb (anti–TSH antibody levels) : 30.03 IU/l (elevated). Ultrasound thyroid revealed increased vascularity in bilateral thyroid lobes with heterogenous appearance. She was started on oral Carbimazole and Propanolol.

Case 2: A 29-year-old healthcare worker with underlying thyrotoxicosis in remission for 7 years presented with symptoms of as heat intolerance, agitation, oligomenorrhea, mood instability, palpitations and diarrhea within 1 month after her 1st dose of SARS-CoV-2 vaccine (Pfizer-BioNTech). Physical examination revealed fine tremors with no thyroid eye signs or goiter present. Results of biochemical workup was as follows: TSH: <0.008 mIU/l (low), FT4: 29.4 pmol/l (elevated), FT3: 8.47 pmol/l (elevated), anti-TPO: 254.8 IU/ml (elevated), anti-TG: 30.13 IU/ml (normal), TSHrAb:<0.8 IU/l (normal). Thyroid ultrasound revealed increased in vascularity. She was started on oral Carbimazole and Bisoprolol.

Case 3: A 30-year-old healthcare worker with underlying thyrotoxicosis in remission for 9 years also presented with lost of weight of 6 kg, heat intolerance and fine tremors, within 1 month after her 1st dose of SARS-CoV-2 vaccine (Pfizer-BioNTech). Physical examination revealed fine tremors with a diffuse goiter present. Results of biochemical workup was as follows: TSH: <0.008 mIU/l (low), FT4: 56.6 pmol/l (elevated), anti-TPO: 375.7 IU/ml (elevated), anti-TG:1691.1 IU/ml (elevated), TSHrAb: <0.8 IU/l (normal). Thyroid ultrasound revealed heterogenicity and increase vascularity in bilateral thyroid lobes. She was started on oral Carbimazole and Propanolol.

Conclusion: This case series reports three cases of autoimmune thyrotoxicosis post vaccination with Pfizer-BioNTech against COVID-19. Any emerging symptoms of thyrotoxicosis post vaccination should prompt clinicians to screen appropriately. However, the benefits of vaccination still outweigh any risks and should be advocated for all patients unless they have other contraindications.