inclusion criteria: * age ≥ 18 year * laboratory (rt-pcr) positive of sars-cov-2 (moderate cases) * chest ct with pneumonia. * sao2/spo2 ratio \> 93% or pao2/fio2 ratio \> 300 mmhg under the condition in the hospital room. * welling to participate and able to give fully informed consent

inclusion criteria: * age ≥ 18 year * laboratory (rt-pcr) positive of sars-cov-2 (moderate cases) * chest ct with pneumonia. * sao2/spo2 ratio \> 93% or pao2/fio2 ratio \> 300 mmhg under the condition in the hospital room. * welling to participate and able to give fully informed consent

inclusion criteria: - age ≥ 18 year - laboratory (rt-pcr) positive of sars-cov-2 (moderate cases) - chest ct with pneumonia. - sao2/spo2 ratio > 93% or pao2/fio2 ratio > 300 mmhg under the condition in the hospital room. - welling to participate and able to give fully informed consent

inclusion criteria: - age ≥ 18 year - laboratory (rt-pcr) positive of sars-cov-2 (moderate cases) - chest ct with pneumonia. - sao2/spo2 ratio > 93% or pao2/fio2 ratio > 300 mmhg under the condition in the hospital room. - welling to participate and able to give fully informed consent