While patients with autoimmune thyroiditis had a significant increase in anti-thyroid peroxidase antibodies (ATPO) and anti-thyroglobulin antibodies (anti-Tg) levels at a 1-month follow-up after contracting the respiratory infection, patients with euthyroidism had a significant decrease in thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) levels. This evidence concerns the gene TPO and respiratory tract infectious disorder.