COVID-19(31) SARS-CoV-2(14) Zinc(13) COVID-19 patient(10) the patient(9) Selenium(8) serum(8) COVID-19 patients(8) micronutrients(8) oxidative stress(8) indicated(7) zinc.(7) trace elements(7) reported(7) Patient(6) two groups(6) patients with COVID-19(6) Mortality(6) disease severity(6) randomized clinical trial(6) Infection(6) two group(5) had no(5) therapy(5) investigated(5) immune system(5) was performed(5) evaluate the effect(5) database(4) Treatment(4)