At the present, no specific antiviral therapy has been approved for treatment of infection by human CoVs. As development of vaccines and compounds for prevention and treatment of infection have been brought to priority status by WHO and governments [56], numerous drug studies have been done or are moving forward. Some of them focus on the CoV fusion/entry process either by inhibition of S1 mediated virus attachment or by blocking of S2 mediated virus-cell membrane fusion, and some of them interfere with viral replication [57].