DENV (serotype 2, strain 16681) and ZIKV (strain BRA/Fortaleza/2015) were propagated in C6/36 and Vero cells, respectively46 (link), 47 (link). Encephalomyocarditis virus (EMCV, EMC strain) was purchased from ATCC and propagated in HEK293T cells6 (link). mutEMCV (EMCV-ZnC19A/C22A), which carries two point mutations in the zinc domain of the L protein18 (link), was kindly provided by Frank J.M. van Kuppeveld (Utrecht University) and was propagated in BHK-21 cells. Sendai virus (strain Cantell) was purchased from Charles River Laboratories. SCoV2 (strain 2019-nCoV/USA_WA½020) was kindly provided by Jae U. Jung (Cleveland Clinic Lerner Research Center) and was propagated in Vero E6-hACE2 cells. All work relating to SCoV2 live virus and SCoV2-RNA was conducted in the BSL-3 facility of the Cleveland Clinic Florida Research and Innovation Center in accordance with institutional biosafety committee (IBC) regulations.