Dear Editor,
We would like to share ideas on the publication “Thyrotoxicosis after COVID-19 vaccination: seven case reports and a literature review” [1]. Lee et al. concluded that “COVID-19 vaccines can cause not only destructive thyroiditis but also AIT… relationship between COVID-19, vaccines, and thyroid diseases” [1]. We agree that the post-COVID-19 vaccination thyroid problem might occur and there might be an association with pathological/abnormal immune response to vaccine. In the present study, a change of thyroxine level is well demonstrated and there is a trend of decreasing when time passes. After vaccination, there is also another important process that might contribute to thyrotoxicosis occurrence. The vaccine can induce increased blood viscosity [2]. The association between hyperviscosity and thyrotoxicosis is proposed [3]. An increasing of blood viscosity is due to rapid increased level of antibody after vaccination and the viscosity will decrease when there is a decline of antibody level. This pattern is the same as observed alteration of thyroid hormone level in the present report by Lee et al. [1]. Finally, if thyroid hormone test is based on immunoassay, an interference, a false aberration of hormone level might be induced by a high blood viscosity [4].
Compliance with ethical standards
Conflict of interest
The authors declare no competing interests.
Footnotes
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.K.A. Lee, Y.J. Kim, H.Y. Jin, Thyrotoxicosis after COVID-19 vaccination: seven case reports and a literature review. Endocrine. 1–3 (2021). 10.1007/s12020-021-02898-5 [DOI] [PMC free article] [PubMed]
- 2.Joob B, Wiwanitkit V. Viscosity after COVID-19 vaccination, hyperviscosity and previous COVID-19. Clin. Appl. Thromb. Hemost. 2021;27:10760296211020833. doi: 10.1177/10760296211020833. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Bussmann YL, Tillman ML, Pagliara AS. Neonatal thyrotoxicosis associated with the hyperviscosity syndrome. J. Pediatr. 1977;90(2):266–268. doi: 10.1016/S0022-3476(77)80648-3. [DOI] [PubMed] [Google Scholar]
- 4.Selby C. Interference in immunoassay. Ann. Clin. Biochem. 1999;36(Pt 6):704–721. doi: 10.1177/000456329903600603. [DOI] [PubMed] [Google Scholar]