Although RNA enzymes were discovered before DNA enzymes, the latter have some distinct advantages. DNA is more cost-effective, and DNA can be made with longer sequence length and can be made with higher purity in solid-phase synthesis. Several studies have shown the usage of DNAzymes to inhibit influenza A and B virus replication in host cells. DNAzymes have also been shown to inhibit the replication of SARS coronavirus (SARS-CoV), Respiratory syncytial virus (RSV), human rhinovirus 14 and HCV