Type I interferons
Type I interferons designate a cluster of antiviral cytokines consisting of the omnipresent α and β subtypes, along with the ω, ε and κ subtypes, inducing large numbers of proteins that can undermine viral replication in host cells (Samuel, 2001). Former researches have revealed that IFN-β was superior against SARS-CoV in comparison with IFN-α (Scagnolari et al., 2004). As for the clinical trial of type I interferons, in China, therapy guidelines for COVID-19 recommend the management of 5 million U of IFN-α via vapor inhalation in patients twice daily with ribavirin as combined therapy (Dong et al., 2020). In the detailed study of Sallard et al., they reported that IFN-β1 might constitute a safe and easy to upscale therapy against COVID-19 in the early stages of the disease. Besides, the in vitro data indicated that this virus might be significantly more sensitive to IFN-I than other CoVs (Sallard et al., 2020).