Distinct Clinical Features of Post-COVID-19 Vaccination Early-onset Graves' Disease

Context: Several case reports of Graves' disease (GD) occurrence after COVID-19 vaccination that are possibly related to the autoimmune syndrome induced by adjuvants (ASIA) were published recently. Objective: The aim of our study was to evaluate possible distinctive features in the presentation and clinical course of patients with GD occurring early (within 4 weeks) after COVID-19 vaccination who attended our Endocrine Unit in 2021. Methods: Patients with a first episode of GD attending a tertiary endocrine center between January 1, 2021, and December 31, 2021, were included. Results: Sixty-four patients with a first episode of GD were seen in 2021: 20 (31.2%) of them had onset within 4 weeks following vaccine administration. Compared with the other 44 patients, the 20 patients with postvaccine early-onset (PoVEO) GD were older (median age 51 years vs 35 years, P = .003) and more likely to be male (40.0% vs 13.6%, P = .018). At diagnosis, the biochemical and immune profiles were similar between the 2 groups. However, at 3 months after starting methimazole, patients with PoVEO GD had significantly lower thyrotropin receptor antibody titer and were taking lower doses of methimazole than the other patients with GD. None in the PoVEO group had sustained free triiodothyronine elevation. Conclusion: This relatively large series suggests that in 2021 PoVEO GD may be a new nosologic entity representing one-third of patients evaluated for new-onset GD in our center. Distinctive features included older age at onset, higher male prevalence, and a better initial biochemical and immunologic response to treatment. Further studies are warranted to clinically and biochemically differentiate these cases from sporadically occurring GD.