the 50% infectious dose of MERS-CoV EMC/2012 strain is less than 1 TCID50 (50% tissue culture infectious doses per milliliter) mice surviving MERS-CoV infection develop serum neutralizing antibody and MERS-CoV S1 protein-specific IgG antibodies by 21 dpi and are fully immune to challenge with 103 TCID50 most mice immunized with a MERS-CoV receptor binding domain-based subunit vaccine S377-588l-Fc plus MF59 adjuvant before being challenged with MERS-CoV recover from mild morbidity and survive intranasal administration of a fusion inhibitor peptide HR2M6 before challenge with MERS-CoV results in reduced lung viral titers and protection from death administration of HR2M6 after exposure to MERS-CoV does not provide therapeutic benefit
