COVID-19(29) SARS-CoV-2(18) Patient(13) SARS-COV-2 infection(11) treated(10) addition(9) Treatment(9) elevated(8) therapy(8) spike(8) Analysis(8) Infection(8) IgG(7) pathogenic(6) Mortality(6) patients(6) Vaccine(6) demonstrated(5) Pneumonia(5) vaccination(5) disease(5) immune response(5) Efficacy(5) domain(5) syndrome(5) booster(4) COVID-19 complication(4) country(4) B.1.351(4) booster vaccination(4)