Unlike SARS subunit vaccines which have been designed based on viral N and M proteins, it appears that very few subunit vaccines have been developed based on the non-S structural protein(s) of MERS-CoV. One study reports the induction of specific antibodies by MERS-CoV N peptides (Yang et al., 2014a), and another report shows that N protein is used for development of vaccines based on viral vector Vaccinia virus, modified Vaccinia Ankara (MVA) (Veit et al., 2018). This may be potentially a consequence of the weak immunogenicity and/or protective efficacy of non-S structural proteins, further confirming the role of MERS-CoV S protein as the key target for the development of MERS vaccines, including subunit vaccines.