* 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; * allergy to any component of the investigational product that have contact with human body; * complicate severe cardiac, hepatic or renal insufficiency; * expected life expectancy \< 1 year; * subjects who are participating in any other clinical study of any investigational drug or medical device; * pregnant or lactating women, or women who plan to become pregnant within the following one year; * any other condition judged as inappropriate to participate in this study by the investigator.

* 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; * allergy to any component of the investigational product that have contact with human body; * complicate severe cardiac, hepatic or renal insufficiency; * expected life expectancy \< 1 year; * subjects who are participating in any other clinical study of any investigational drug or medical device; * pregnant or lactating women, or women who plan to become pregnant within the following one year; * any other condition judged as inappropriate to participate in this study by the investigator.

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; allergy to any component of the investigational product that have contact with human body; complicate severe cardiac, hepatic or renal insufficiency; expected life expectancy < 1 year; subjects who are participating in any other clinical study of any investigational drug or medical device; pregnant or lactating women, or women who plan to become pregnant within the following one year; any other condition judged as inappropriate to participate in this study by the investigator.

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; allergy to any component of the investigational product that have contact with human body; complicate severe cardiac, hepatic or renal insufficiency; expected life expectancy < 1 year; subjects who are participating in any other clinical study of any investigational drug or medical device; pregnant or lactating women, or women who plan to become pregnant within the following one year; any other condition judged as inappropriate to participate in this study by the investigator.