To evaluate the binding affinity between three launched or clinical mAbs and two variant RBD, MM/GBSA calculations were carried out with RBDWT as control based on each MD runs lasting 200ns in triplicate. As shown in Table , the relative binding free energy to Etesevimab and BD-368-2 between WT and Delta RBD is -25.44, -17.21 kcal/mol, which means this variant may impair the effectiveness of these two antibodies.