Subacute thyroiditis following influenza vaccination is a rarely reported condition.

Can flu shot affect thyroid?

While some with thyroid disease may worry about the flu shot's effect on their already challenged immune system, others may be concerned about reports that the vaccine can induce a relapse of thyroid symptoms. Most of these concerns are unfounded. The annual flu shot is recommended for everyone.

Can a vaccine affect your thyroid?

Summary: Vaccines have been shown to trigger an immune response that leads to a broad spectrum of autoimmune diseases, including autoimmune thyroid disease.