Endocrine Abstracts

Background: The Covid-19 pandemic caused by the severe-acute-respiratory-syndrome-coronavirus-2 (SARS-CoV-2) determined millions of deaths worldwide, thus at the end of 2020 a massive vaccination campaign has been launched. SARS-CoV-2 infection and vaccines have been associated with several thyroid disorders, especially subacute thyroiditis (SAT), Graves’ disease (GD) and orbitopathy (GO). We studied the occurrence of SAT and GO following SARS-CoV-2 infection or vaccination in our Centre.

Methods: We recorded all consecutive cases of SAT (new diagnosis) from February 2020 and GO (new diagnosis or sudden worsening) from June 2021 onwards, noting if occurred within 1 month after SARS-CoV-2 infection or vaccines.

Results: Up to March 2022 we have recorded 25 SAT and 28 GO. The onset of SAT occurred within 1 month from SARS-CoV-2 vaccination in 8/25 (32%) and from SARS-CoV2 infection in 4/25 (16%). Among the 28 GO, 11 (39%) occurred within 1 month from SARS-CoV2-vaccination (9 new diagnosis and 2 worsening) and 1 from SARS-CoV2-infection (new diagnosis). Interestingly, 5 (18%) had a GO onset apparently unrelated to SARS-CoV2-vaccination, however had developed GD hyperthyroidism within one month from it. The 19 patients developing SAT or GO after SARS-CoV-2 vaccination had received Pfizer (n = 12), Moderna (n = 3) or AstraZeneca (n = 4); symptoms developed following the first, second or third dose in 8 (42%, mean +13 days), 5 (26%, mean +17 days) and 6 (31% mean +10 days) cases, respectively. A previous documented SARS-CoV-2 infection several months before the vaccination had occurred in 1/19 patients (5%). The mean age of patients was 54±18.17 years (range 21-83 years) and females were 14/19 (73%). A previous history of thyroid disease was present in 3/19 (16%): one subclinical hypothyroidism, one euthyroid nodular goitre, one euthyroid Hashimoto’s thyroiditis. A family history of thyroid disorders was present in 10/19 (52%) patients.

Conclusions: SARS-CoV-2 vaccines seem to be associated with the onset of SAT and the onset or worsening of GO. Possible mechanisms involve the interaction of the spike protein with the ACE-II receptor expressed in thyroid tissue, a cross-reactivity of the spike protein with thyroid self-proteins or an immune reaction induced by adjuvants (ASIA syndrome). Many patients had a positive family history for thyroid disorders, thus a genetic predisposition is likely involved. Until more safety data about SARS-CoV-2 vaccines will be available, caution and strict monitoring of injected individuals is suggested, especially those predisposed to thyroid disorders or autoimmunity.