SARS-CoV-2(136) COVID-19(104) Infection(45) Protein(42) SARS-CoV-2.(41) virus(41) Mutation(41) binding(40) Receptor binding domain(39) caused(39) RBD(39) coronavirus(37) pandemic(36) variant(36) respiratory(34) Vaccine(34) effective(33) ACE2(32) acute respiratory syndrome(32) variants(31) the SARS-CoV-2(29) antibody(28) SARS-COV-2 infection(27) develop(27) Spike protein(27) reduced(26) Treatment(26) reported(26) mechanism(25) in vitro(25)