Table 1.

S protein-based vaccines against MERS-CoV.

Candidate	Antigen	Animal model	Vaccine regimens	Efficacy or observed effects	Reference
MVA-S	S	Mice	i.m. administered of 1 × 108 PFU twice at a 3-weeks interval	ND	(Song et al., 2013)
		Ad5-hCD26-transduced mice	s.c. administered of 1 × 108 PFU twice at a 3-weeks interval	100% protection (n = 5)	(Volz et al., 2015)
		Ad5-hCD26-transduced mice	i.m. administered of 1 × 108 PFU twice at a 3-weeks interval	100% protection (n = 5)
		Dromedaries	i.n. administered of 2 × 108 PFU and i.m. Injection of 1 × 108 at the neck twice at a 4-weeks interval	Significant reduction of excreted virus (n = 4)	(Haagmans et al., 2016)
VRP-S	S	Ad5-hCD26-transduced mice	1 × 105 IU delivered in footpad twice at 4-week interval	100% protection (n = 3−4)	(Zhao et al., 2014)
DNA	S-DNA and S1-protein	Mice	20 μg of S DNA were i.m. delivered followed by EP twice at 3-week interval and boosted with 10 μg of S1 protein plus Ribi 3 weeks later	ND	(Wang et al., 2015)
		Rhesus macaque	1 mg of S DNA were i.m. delivered followed by EP twice at 4-week interval and boosted with 100 μg of S1 protein plus AlPO4 4 weeks later	100% protection (n = 6)
	S	Mice	25 μg of DNA i.m. delivered followed by EP three times at 2-week intervals	ND	(Muthumani et al., 2015)
		Dromedaries	EP-enhanced i.m. delivery three times at 4-week intervals	ND
		Rhesus macaque	0.5 mg or 2 mg of DNA i.m. delivered followed by EP three times at 3-week intervals	100% protection (n = 4 for each dosage)
subunit	RBD-Fc	Ad5-hCD26-transduced mice	10 μg/mice of RBD-Fc plus MF59 s.c. delivered three times at 3-week interval	100% protection (n = 4)	(Zhang et al., 2015)

Abbreviations: i.m. – intramuscular, s.c. – subcutaneous; i.n. – intranasal; ND – not determined; EP – electroporation.