Patients with Hashimoto’s thyroiditis present higher immune response to COVID-19 mRNA vaccine compared to normal individuals

Aim To evaluate the response (titers of anti-COVID-19 antibodies) to COVID-19 mRNA vaccine of patients with Hashimoto’s thyroiditis and normal individuals. Patients and methods Twenty-four patients with Hashimoto’s thyroiditis and 51 normal individuals were studied after the third dose of the vaccine. Results Patients with Hashimoto’s thyroiditis showed significantly higher immune response after the third dose of the COVID-19 mRNA vaccine compared with normal individuals ( p = 0.020). After elimination of the four smokers with Hashimoto’s thyroiditis, the immune response between the remaining 20 non-smoking patients compared with the response of the 23 non-smoking normal individuals was not different ( p = 0.564). There was a significant positive correlation of the anti-COVID-19 antibodies with BMI ( p = 0.029) but not with waist circumference in the patients with Hashimoto’s thyroiditis ( p = 0.054). Similar correlations were not found in normal individuals. Waist circumference could be considered as representative of visceral adipose tissue. In obese normal individuals (BMI ≥ 30), anti-COVID-19 antibodies were not different from those in lean normal individuals (BMI < 25). In obese patients with Hashimoto’s thyroiditis, anti-COVID-19 antibodies were significantly higher compared to those in lean patients ( p = 0.013). Median anti-COVID-19 antibody titer in obese patients with Hashimoto’s thyroiditis was also significantly higher compared to that in obese normal individuals ( p = 0.009). Conclusions Patients with Hashimoto’s thyroiditis show significantly higher immune response after the third dose of the COVID-19 mRNA vaccine compared with normal individuals. Obese patients with Hashimoto’s thyroiditis show additionally a significantly higher immune response compared with lean patients.