Neutralizing Abs can fight against viral infections by blocking binding to cellular receptors or by interfering with viral fusion. Besides, in the case of enveloped viruses, the Abs can recruit effector cells or the complement, thus allowing the destruction of the infected cells or the lysis of the viral particles [6]. The S1 domain contains most of the epitopes recognized by nAbs during infection. The RBD located in this S1 domain would be the most important target for nAbs against SARS-CoV, MERS-CoV and the novel coronavirus SARS-CoV-2 [[26], [27], [28], [29]]. More specifically, certain secondary structures such as extended loops seem to be particularly immunogenic.