COVID-19(20) Patient(9) coronavirus disease(8) SARS-CoV-2(7) coronavirus(7) Mild(7) Stroke.(6) acute respiratory syndrome(6) Myocardial infarction(6) 95% confidence interval(6) herpes zoster(6) 95% CI(6) Mortality(6) age(5) acute respiratory syndrome coronavirus(5) Pneumonia(5) comparable(5) Coronavirus disease 2019(5) patients(5) retrospective cohort study(5) Infection(4) enzyme-linked immunosorbent assay(4) Severe acute respiratory syndrome coronavirus 2.(4) disease outbreaks(4) Negative conversion(4) viral clearance(4) median(4) single center(4) antibody formation(4) Hepatitis B virus(4)