COVID-19(23) SARS-CoV-2(18) pandemic(13) Spread(11) virus(9) coronavirus(9) Result(8) Vaccine(7) Patient(7) Treatment(7) reported(7) COVID-19 pandemic(7) measure(7) Research(6) outbreak(6) effective(6) highlight(6) death(6) acute respiratory syndrome(5) Infection(5) Transmission(5) disease(4) Prevent(4) vaccination(4) Health(4) caused(4) Abstract(4) Evidence(4) required(4) viral infection(4)