ABSTRACT
Since the beginning of the wide-scale anti-Coronavirus disease 2019 (COVID-19) vaccination program, sporadic cases of thyroid disease following vaccination have been reported. We describe 19 consecutive cases of COVID vaccine-related thyroid disease. Medical records were reviewed for 9 patients with Graves' disease (GD) and 10 with Thyroiditis, all of whom were diagnosed following COVID-19 vaccination. In the GD group, the median age was 45.5 years, female/male(F/M) ratio 5:4, thyroid-stimulating immunoglobulins were elevated in seven patients. The median time from vaccination to diagnosis was 3 months. Methimazole treatment was given to all but one patient. At a median follow-up of 8.5 months from vaccination, three patients were still on methimazole, five went into remission (data were missing for one). In the Thyroiditis group, the median age was 47 years, the F/M ratio 7:3. Thyroiditis was diagnosed after the first, second, and third doses in one, two, and seven patients, respectively. The median time from vaccination to diagnosis was 2 months. TPO antibodies were positive in three patients. All patients were euthyroid off medication at the last visit. Six patients were diagnosed in the hypothyroid phase at 2.5 months from vaccination. Four resolved spontaneously at 3, 6, 4, and 8 months; the other two were treated with thyroxine at 1.5 and 2 months from vaccination and remained on treatment at their last visit, at 11.5 and 8.5 months, respectively. Thyroid disease should be included among possible complications of COVID-19 vaccine and either a late onset or delayed diagnosis should be considered.