LBODP093 Evaluation Of The Impact Of Covid-19 Vaccines On Thyroid Function And Autoimmunity And The Potential Influence Of Pre-existing Thyroid Autoimmunity On Neutralizing Antibody Responses

• Published in: Journal of the Endocrine Society Vol. 6; no. Supplement_1; p. A738
• Main Authors: Lui, David, Lee, Chi H, Cheung, Chloe, Cheung, Venus, Mak, Jimmy, Fong, Carol, Lui, Brian, Chow, Wing Sun, Lee, Alan, Tam, Anthony, Pang, Polly, Ho, Tip Yin, Tan, Kathryn, Woo, Yu Cho, Hung, Ivan, Lam, Karen
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 01.11.2022
• Subjects: Thyroid
• ISSN: 2472-1972; 2472-1972
• DOI: 10.1210/jendso/bvac150.1523

Abstract Objectives There are concerns for COVID-19 vaccination in causing thyroid dysfunction and triggering thyroid autoimmunity. Also, data on the impact of pre-existing thyroid autoimmunity on COVID-19 vaccination efficacy are limited. We evaluated the impact of COVID-19 vaccination on thyroid function and antibodies, and the influence of pre-existing thyroid autoimmunity on neutralizing antibody (NAb) responses. Methods Adults without history of COVID-19 or thyroid disorders who received COVID-19 vaccination between 14 June 2021 and 8 August 2021 at three vaccination centers were recruited. All participants received two doses of vaccines. Thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) antibodies were measured at baseline and 8 weeks after the first dose of vaccination. Post-vaccination NAb against SARS-CoV-2 receptor-binding domain was measured. Results In total, 215 individuals were included (129 BNT162b2 [60%] and 86 CoronaVac [40%] recipients): mean age 49.6 years, 37.2% men, and 12.1% positive for anti-TPO/anti-Tg at baseline. After vaccination, TSH levels did not change (p=0.225), but fT4 slightly increased (from 12. 0±1.1 to 12.2±1.2 pmol/L, p<0. 001) and fT3 slightly decreased (from 4.1±0.4 to 4. 0±0.4 pmol/L, p<0. 001). Only 3 patients (1.4%) had abnormal thyroid function after vaccination: two occurred among BNT162b2 recipients - both were subclinical thyrotoxicosis (TSH 0.32mIU/L, fT4 11.51pmol/L and fT3 4.40pmol/L; TSH 0.34mIU/L, fT4 12.67pmol/L and fT3 4.22pmol/L; both were anti-TPO and anti-Tg negative before and after vaccination); one occurred among CoronaVac recipients - isolated mild low fT3 (TSH 0.90mIU/L, fT4 9.94pmol/L and fT3 2.33pmol/L; anti-TPO/Tg negative before and after vaccination). All three recipients were asymptomatic. Both anti-TPO and anti-Tg titers increased modestly after vaccination (anti-TPO: from 7.50 [IQR: 5.90-11.2] to 9.80 IU/mL [IQR: 7.80-13.1], p<0. 001; anti-Tg: from 12.4 [IQR: 11.1-14.9] to 15.7 IU/mL [IQR: 14.2-18.2], p<0. 001), without significant changes in anti-TPO/Tg positivity. Changes in thyroid function and anti-thyroid antibodies were generally consistent between BNT162b2 and CoronaVac recipients, although anti-TPO titer rise was greater after BNT162b2 (p<0. 001). NAb responses were similar between individuals with and without pre-existing thyroid autoimmunity (p=0.855). Conclusion COVID-19 vaccination was associated with a modest increase in anti-thyroid antibody titers. Anti-TPO increase was greater among BNT162b2 recipients. However, there was no clinically significant thyroid dysfunction 8 weeks post-vaccination. NAb responses were not influenced by pre-existing thyroid autoimmunity. Our results provided important reassurance to people to proceed to COVID-19 vaccination. Presentation: No date and time listed