COVID-19(222) SARS-CoV-2(118) Adaptive immunity(91) Patient(89) immunology(85) individual(66) T cells(62) T cell(58) Infectious disease(57) coronavirus disease(53) Mild(46) antibody(46) coronavirus(46) significantly(44) SARS-COV-2 infection(44) Coronavirus disease 2019(42) disease(42) immune(41) variant(41) neutralizing antibody(38) Vaccine(38) plasma(37) severe COVID-19(37) Spike protein(35) acute respiratory syndrome(34) Treatment(34) Immunity(34) identify(34) correlated(33) characterized(33)