inclusion criteria: all subjects participating in this clinical study must meet all of the following criteria: 1. according to the diagnosis and treatment protocol for covid-19 (trial version 5), under the premise of meeting the diagnostic criteria of moderate covid-19, the subjects should meet one of the following three conditions: ① respiratory rate (rr): ≥ 20 times/min; ② in the state of air absorption and rest, the peripheral oxygen saturation is lower than 95%; ③ arterial partial pressure of oxygen (pao2)/fio2: ≤ 400 mmhg (1mmhg=0.133 kpa). 2. ≥18 years old and ≤85 years old subjects with normal autonomous judgment, regardless of gender and region; 3. subjects voluntarily participate in the study and have signed the informed consent form.

inclusion criteria: all subjects participating in this clinical study must meet all of the following criteria: 1. according to the diagnosis and treatment protocol for covid-19 (trial version 5), under the premise of meeting the diagnostic criteria of moderate covid-19, the subjects should meet one of the following three conditions: ① respiratory rate (rr): ≥ 20 times/min; ② in the state of air absorption and rest, the peripheral oxygen saturation is lower than 95%; ③ arterial partial pressure of oxygen (pao2)/fio2: ≤ 400 mmhg (1mmhg=0.133 kpa). 2. ≥18 years old and ≤85 years old subjects with normal autonomous judgment, regardless of gender and region; 3. subjects voluntarily participate in the study and have signed the informed consent form.

inclusion criteria: all subjects participating in this clinical study must meet all of the following criteria: according to the diagnosis and treatment protocol for covid-19 (trial version 5), under the premise of meeting the diagnostic criteria of moderate covid-19, the subjects should meet one of the following three conditions: ① respiratory rate (rr): ≥ 20 times/min; ② in the state of air absorption and rest, the peripheral oxygen saturation is lower than 95%; ③ arterial partial pressure of oxygen (pao2)/fio2: ≤ 400 mmhg (1mmhg=0.133 kpa). ≥18 years old and ≤85 years old subjects with normal autonomous judgment, regardless of gender and region; subjects voluntarily participate in the study and have signed the informed consent form.

inclusion criteria: all subjects participating in this clinical study must meet all of the following criteria: according to the diagnosis and treatment protocol for covid-19 (trial version 5), under the premise of meeting the diagnostic criteria of moderate covid-19, the subjects should meet one of the following three conditions: ① respiratory rate (rr): ≥ 20 times/min; ② in the state of air absorption and rest, the peripheral oxygen saturation is lower than 95%; ③ arterial partial pressure of oxygen (pao2)/fio2: ≤ 400 mmhg (1mmhg=0.133 kpa). ≥18 years old and ≤85 years old subjects with normal autonomous judgment, regardless of gender and region; subjects voluntarily participate in the study and have signed the informed consent form.

inclusion criteria: all subjects participating in this clinical study must meet all of the following criteria: 1. according to the diagnosis and treatment protocol for covid-19 (trial version 5), under the premise of meeting the diagnostic criteria of moderate covid-19, the subjects should meet one of the following three conditions: ① respiratory rate (rr): ≥ 20 times/min; ② in the state of air absorption and rest, the peripheral oxygen saturation is lower than 95%; ③ arterial partial pressure of oxygen (pao2)/fio2: ≤ 400 mmhg (1mmhg=0.133 kpa). 2. ≥18 years old and ≤85 years old subjects with normal autonomous judgment, regardless of gender and region; 3. subjects voluntarily participate in the study and have signed the informed consent form.

inclusion criteria: all subjects participating in this clinical study must meet all of the following criteria: 1. according to the diagnosis and treatment protocol for covid-19 (trial version 5), under the premise of meeting the diagnostic criteria of moderate covid-19, the subjects should meet one of the following three conditions: ① respiratory rate (rr): ≥ 20 times/min; ② in the state of air absorption and rest, the peripheral oxygen saturation is lower than 95%; ③ arterial partial pressure of oxygen (pao2)/fio2: ≤ 400 mmhg (1mmhg=0.133 kpa). 2. ≥18 years old and ≤85 years old subjects with normal autonomous judgment, regardless of gender and region; 3. subjects voluntarily participate in the study and have signed the informed consent form.