Since all the mutations were identified from live viral strains in COVID-19 patients, our results revealed that the furin cleavage site may not be required for SARS-CoV-2 to enter human cells in vivo, which agrees with the in vitro experimental results showing that SARS-CoV-2, with deletion of the furin cleavage site, could still enter the cell lines of humans, African green monkeys, and bay hamsters (Walls et al., 2020). This evidence concerns the gene FURIN and COVID-19.