Among the validated variants in MX1, two promoter single-nucleotide polymorphisms (-123C > A, rs17000900; -88G > T, rs2071430) near the IFN-stimulated response element (ISRE) have been frequently reported the association with various viral diseases, including hepatitis C virus(HCV) [14], enterovirus 71(EV71) [15] and SARS-CoV [16–18]. Here, MX1 is linked to viral load.