MERS‐4 and MERS‐27 are monoclonal antibodies targeting the RBD of MERS‐CoV S that were discovered in a nonimmune yeast‐display scFv library screening. The more active MERS‐4 potently blocked the infection of DPP4‐expressing Huh‐7 cells with pseudotyped MERS‐CoV (IC50, 0.056 μg/mL). It also prevented MERS‐CoV‐induced cytopathogenic effects in MERS‐infected Vero E6 cells (IC50, 0.5 μg/mL). 42