The extra X chromosome exerts a stronger influence on the immune system, and various molecules, including toll-like receptor 8 (TLR8), CD154 (CD40 or CD40L ligand), and CX3C-motif chemokine receptor 3 (CXCR3), appear overexpressed in females, with favorable consequences regarding a good response to viral infections and vaccinations. Here, TLR8 is linked to viral infectious disease.