Post-COVID-19 Vaccination and Thyrotoxicosis (ASIA Syndrome): Single-Centre Experience from India with Review of Literature

Introduction: Thyrotoxicosis is not uncommon after immunization. It is known as 'autoimmune/autoinflammatory syndrome by adjuvants (ASIA syndrome)' and is caused by immunological reaction to adjuvants. However, there is insufficient information on thyrotoxicosis after COVID-19 vaccination in the Indian subcontinent.

Aims/objectives: To investigate the spectrum of thyrotoxicosis after COVID-19 immunization.

Settings and design: A single-centre retrospective study was conducted at a tertiary care academic institute in India.

Materials and methods: We studied the clinical symptoms, biochemical markers, imaging characteristics and treatment of every patient who was diagnosed with thyrotoxicosis within 60 days of receiving the COVID-19 vaccine.

Results: Following COVID-19 vaccination, we diagnosed ten people (mean age 39.9 years, range 22-63 years) with thyrotoxicosis [Graves' disease (GD, n-6) and subacute thyroiditis (SAT, n-4)]. The typical duration for symptoms to appear was 2 to 60 days. The majority of patients (n-9) received the COVISHIELD™ vaccine, whereas only one received the COVAXIN^® vaccine. After vaccination, two patients with GD developed mildly severe Graves' orbitopathy, with symptoms emerging two days and sixty days later, respectively. Anti-thyroid drugs (methimazole or carbimazole) were required for all GD patients. All SAT patients were treated conservatively with nonsteroidal anti-inflammatory medications and had positive outcomes.

Conclusions: SAT, GD and GO may occur as a manifestation of ASIA syndrome, following immunization with COVISHIELD™ and COVAXIN^®. Despite the obvious benefits of the COVID-19 vaccine, clinicians should be aware of any potential autoimmune and inflammatory thyroid problems.