The RBDs of SARS-CoV and MERS-CoV contain multiple conformation-dependent neutralizing epitopes that induce more potent neutralizing antibodies and protective efficacy against SARS-CoV and MERS-CoV infections, respectively, than other regions in S protein [5,8,9]. Modification of MERS-CoV S-RBD amino acid residues based on the structure design could improve its protection against MERS-CoV infection [9], suggesting that 2019-nCoV S-RBD or modified S-RBD of other coronavirus may be applied for developing 2019-nCoV vaccines. Of course, the RBD-containing S and S1 of a coronavirus, e.g. 2019-nCoV, can also be used for vaccine development [8].