This S protein fuses with the cell membrane and helps the syncytial formation and delivering of viral nucleocapsids into the cell for further replication [116] and as per reports, neutralizing antibodies against receptor-binding domain (RBD) of S protein of SARS-CoV [117] and MERS-CoV [45, 118, 119] successfully neutralized those infections. Here, PROS1 is linked to infection.