Levels of mRNAs for IFNβ1 and IFN response gene proteins Mx1, a GTPase induced by type I and type III IFNs38, and IFN-induced protein with tetratricopeptide repeats (IFIT)-1 were upregulated after infection with both YFV and ZIKV with the greatest response induced by YFV. Here, IFNB1 is linked to infection.