To identify the downstream effectors of IFN antiviral activity, we applied a functional genetic approach to DENV because an estimated 3.6 billion of the global population of 7.4 billion people (49%) live in regions at risk for infection, and DENV endemicity is spreading (Wilder-Smith and Gubler, 2008; Louis et al., 2014; Messenger et al., 2014; Butterworth et al., 2016). Here, IFNA1 is linked to infection.