Hydrogen-Oxygen Generator With Nebulizer for Rehabilitation Treatment of COVID-19

Inclusion Criteria: * Male and female subjects aged between 18 and 75 years old (inclusive); * Subjects previously hospitalized due to COVID-19, who are recovered and discharged with negative results for COVID-19 and released from quarantine; * Known symptoms of respiratory dysfunctions (such as dyspnea), and / or neurological/psychological dysfunction (such as sleep disorders, anxiety, and depression) and / or somatic dysfunction (such as fatigue); * Borg dyspnea or fatigue score before study treatment ≥ 1 (please refer to Appendix 2: Borg Scale for specific information), and PSQI score ≥ 2 (please refer to Appendix 3: PSQI Scale for specific information); * Subjects who are willing to participate and provided written informed consent form. Exclusion Criteria: * Subjects with known malignant tumor; * Subjects with known moderate or severe pulmonary infection; * Subjects with mucosa injury in upper respiratory tract, for whom no inhalation treatment can be provided; * Subjects who are intolerable to inhalation treatment; * Subjects with moderate or severe disabilities; * Subjects with mental disorders or cognitive impairment who are unable to provide consent; * Subjects with neurological disease accompanied with sleep disorders for which medical intervention is provided before the diagnosis of COVID-19. * Subjects with any immunodeficiency (for example, subjects requiring chronic treatment with any corticosteroid or other immunosuppressants) judged by the investigator; * A…