Autoimmune and inflammatory thyroid diseases following vaccination with SARS-CoV-2 vaccines: from etiopathogenesis to clinical management.

Since the Covid-19 pandemic emerged in 2019, several adenoviral-vectored, mRNA-based and inactivated whole-virus vaccines have been developed. A massive vaccination campaign has been undertaken around the world, and an increasing number of SARS-CoV-2 vaccine-induced thyroid diseases have been described in the literature. Subacute thyroiditis has been reported in 52 patients, mean age 45.5 ± 1.8 years, mainly in women (n = 39). Graves' disease is more frequent in women (n = 22) than in men (n = 10), mean age 46.2 ± 2.6 years, reported as new onset, recurrent or exacerbation of well-controlled hyperthyroidism. The mean time to symptoms onset is 9.0 ± 0.8 days in subacute thyroiditis, and 15.1 ± 2.6 days in Graves' patients. Rare patients (n = 6) present silent or painless autoimmune thyroiditis. Thyroid function and autoimmune tests, inflammatory markers, thyroid echography with colour flow Doppler, radio-activity uptake on thyroid scan, medical treatment and follow-up are described and compared in patients with SARS-CoV-2 vaccine-induced thyroid diseases. The underlying pathogenic mechanisms of vaccine-induced thyroid diseases, molecular mimicry (various SARS-CoV-2 proteins sharing a genetic homology with a large heptapeptide human protein) or autoimmune/inflammatory syndrome induced by adjuvants (ASIA) are discussed in the context of predisposition or genetic susceptibility. The benefits of SARS-CoV-2 vaccination far outweigh the potential vaccine-induced adverse effects, but clinicians should be aware of possible autoimmune and inflammatory thyroid diseases, and can advise patients to seek medical assistance when experiencing anterior neck pain, fever or palpitations following SARS-CoV-2 vaccines. Further studies are warranted to investigate the etiopathogenesis and to clarify the factors which predispose patients to SARS-CoV-2 vaccine-induced thyroid diseases.