Development of effective vaccines is urgently needed to control the spread of emerging MERS-CoV infections. While viral vector-based and live-attenuated virus-based vaccines have potential for providing effective immunity, subunit vaccines will offer the safestmeans for prevention. Although subunit-based vaccines might induce less immunogenicity than the other vaccine types, their effi-cacy can be significantly improved by rational design based on the structural analysis of RBD of MERS protein and by identification of the most stable and critical neutralizing fragment of RBD,while eliminating non-neutralizing epitopes through immunofocusing