SARS-CoV-2(476) Infection(311) COVID-19(287) virus(276) Viral(241) coronavirus(228) SARS-COV-2 infection(223) Protein(198) respiratory(185) Cell(152) Vaccine(150) Host(149) virus(136) identify(131) Spike protein(127) caused(127) viruses(126) pandemic(125) variant(124) mechanism(123) disease(122) Author(122) antibody(121) Mutation(120) expression(119) Treatment(118) demonstrated(118) acute respiratory syndrome(118) binding(117) Critical(117)