1.Written informed consent has been obtained from the participants with the age of over 20 years at the time of signing the informed consent.2.SARS-CoV-2 infection is diagnosed by RT-PCR within 72 hours before starting drug administration.3.Less than 6 days from onset of COVID-19 symptoms to starting the administration of the investigational drug. The symptoms are defined as one or more of the following: fever (37.5 or higher), respiratory symptoms (cough, shortness of breath, chest pain, sore throat, running nose, nasal congestion, etc.), headache, malaise, abdominal pain, diarrhea, nausea, vomiting, loss of smell, loss of taste, or other COVID-19 symptoms defined by investigators or physicians. 4.Have at least one of the following findings.Oxygen saturation (SpO2) measured by pulse oximeter is less than 96% but more than 93%.Chest X-ray or CT scan shows pneumonia findings suggestive of COVID-19 infection

1.Written informed consent has been obtained from the participants with the age of over 20 years at the time of signing the informed consent.2.SARS-CoV-2 infection is diagnosed by RT-PCR within 72 hours before starting drug administration.3.Less than 6 days from onset of COVID-19 symptoms to starting the administration of the investigational drug. The symptoms are defined as one or more of the following: fever (37.5 or higher), respiratory symptoms (cough, shortness of breath, chest pain, sore throat, running nose, nasal congestion, etc.), headache, malaise, abdominal pain, diarrhea, nausea, vomiting, loss of smell, loss of taste, or other COVID-19 symptoms defined by investigators or physicians. 4.Have at least one of the following findings.Oxygen saturation (SpO2) measured by pulse oximeter is less than 96% but more than 93%.Chest X-ray or CT scan shows pneumonia findings suggestive of COVID-19 infection