efficacy is similar due to conservation of the receptor binding domain[RBD] of spike protien[S] the RBDab is billed as the gold standard neutralizing antibody as when it binds to RBD of the S protien, that particular S protien is no longer able to bind to its ligand [ACE2]
should we see a variant that escapes this RBD Antibody mechanism then there will be a possibility of escape, and concommitant requirement to tweak the vaccine antigen.