"Introduction
... Despite the robust beneficial data on the SARS-CoV-2 mRNA vaccine, adverse effects of the vaccines related to endocrine disorders have also recently been highlighted. Among the endocrine organs possibly targeted as adverse effects of the vaccine, the thyroid gland is the most common one. Notably, an increasing number of cases of new-onset or relapse of Graves’ disease (GD) has been recently reported to occur following the SARS-CoV-2 mRNA vaccines. Such case reports and series have raised speculation of the development of thyroid autoimmunity due to the mRNA vaccine. However, there is limited epidemiological evidence or basic findings to clarify if the SARS-CoV-2 mRNA vaccine induces thyroid autoimmunity. Furthermore, if the mRNA vaccine disrupts thyroid autoimmunity, further clinically important questions arise: if the disruption has the potential to induce functionally overt situations, how long does the vaccine affect thyroid autoimmunity, and what factors predict its disruption? ...
Materials and methods
Study design and timeline
Among the 90 remaining participants, samples from 70 participants whose serum samples at all the time points were sufficient for measurement of thyroid autoimmune antibodies and functions were retrospectively analyzed...
Results
Clinical characteristics and time course of anti-SARS-CoV-2 S antibodies
During the period between 32 weeks after the administration of the second dose and 4 weeks after the third dose, the median antibody titer increased from 325 (IQR, 169-546) U/mL to 17627 (IQR, 10898-24175) U/mL. The period from 32 weeks after the administration of the second dose to 4 weeks after the third dose was 91 (IQR, 91-93) days. All participants had an increase in the antibody titer...
Discussion
... One of the main findings of this study is that TRAb [thyroid-stimulating hormone receptor antibody] was significantly increased by the first two doses of the SARS-CoV-2 BNT162b2 vaccine and that the effect was still evident at 32 weeks. Furthermore, although without statistical significance, TRAb tended to be additionally increased by the third dose of the vaccine within 4 weeks. Since most of the participants (67/70) had baseline TRAb under the lower limit of the reference range (<0.8 IU/L), it is assumed that the SARS-CoV-2 BNT162b2 vaccine not only disrupted the steady state of GD, but also newly induced the disruption of thyroid autoimmunity. These findings support previous cases and series that showed the relapse or even new onset of GD potentially associated with the SARS-CoV-2 BNT162b2 mRNA vaccine. Similar to TRAb, TgAb was also increased after the third dose, additionally supporting the evidence about the disruption of thyroid autoimmune owning to the vaccine."
© 2023 Morita, Takagi, Inaba, Furukawa, Kishimoto, Uraki, Shimo, Takeshima, Uraki, Doi, Imagawa, Kokawa, Konami, Hara, Hara, Sone, Furuta, Nishi, Doi, Tamura and Matsuoka.
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