The radical S-adenosyl-methionine (SAM) domain-containing protein 2 (RSAD2), also known as virus inhibitory protein endoplasmic reticulum-associated, IFN-inducible (Viperin), ranks among the most highly induced ISGs upon stimulation with IFNs, dsRNA, viral infections; it is also induced upon lipopolysaccharide stimulation and bacterial infections [3–5]. This evidence concerns the gene RSAD2 and viral infectious disease.