A study for the key technology of mesenchymal stem cells exosomes atomization in the treatment of novel coronavirus pneumonia (COVID-19)

INTERVENTION: Exocrine group:Aerosol inhalation of exosomes;Control group:Blank; CONDITION: Novel Coronavirus Pneumonia (COVID‐19) PRIMARY OUTCOME: Lung CT; SECONDARY OUTCOME: Nucleic acid detection of pharyngeal test;Leukocytes and lymphocytes in blood routine; INCLUSION CRITERIA: Patients meet the diagnostic criteria "Diagnosis and treatment of novel coronavirus pneumonia (trial version fifth)"for suspected cases outside Hubei Province: combined with the following epidemiological and clinical manifestations: epidemiological history 1. Patients with travel or residence history in Wuhan and surrounding areas or other communities with case reports within 14 days before the onset of the disease; 2. Patients with a novel coronavirus infection (positive for nucleic acid detection) within 14 days before onset;, 3. Patients with fever or respiratory symptoms from Wuhan and surrounding areas or from the community with case report had been contacted within 14 days before the onset of the disease; 4. Clustering disease; clinical manifestations: (1) fever and / or respiratory symptoms; (2) having the above‐mentioned imaging characteristics of pneumonia; (3) normal or reduced leukocyte count or lymphocyte count in the e