1. volunteers have suspected symptoms of covid-19 when enrolled, such as dry throat, sore throat, cough, etc. 2. the covid-19 antigen quick test kit is positive when volunteers are enrolled. 3. fever, temperature \> 37.0°c. 4. have received a second covid-19 vaccine booster immunization. 5. have a history of serious adverse reactions related to the vaccine and/or have a history of severe allergic reactions to any component of the investigational vaccine (only applicable to the vaccine groups). 6. pregnant or lactating women. 7. hiv infection, tuberculosis, low immunity caused by disease or long-term medication. 8. acute disease or acute onset of chronic disease. 9. epilepsy and other progressive neurological disorders. 10. other situations that are not suitable for participating in this research, according to the judgment of the researcher.

1. volunteers have suspected symptoms of covid-19 when enrolled, such as dry throat, sore throat, cough, etc. 2. the covid-19 antigen quick test kit is positive when volunteers are enrolled. 3. fever, temperature \> 37.0°c. 4. have received a second covid-19 vaccine booster immunization. 5. have a history of serious adverse reactions related to the vaccine and/or have a history of severe allergic reactions to any component of the investigational vaccine (only applicable to the vaccine groups). 6. pregnant or lactating women. 7. hiv infection, tuberculosis, low immunity caused by disease or long-term medication. 8. acute disease or acute onset of chronic disease. 9. epilepsy and other progressive neurological disorders. 10. other situations that are not suitable for participating in this research, according to the judgment of the researcher.

volunteers have suspected symptoms of covid-19 when enrolled, such as dry throat, sore throat, cough, etc. the covid-19 antigen quick test kit is positive when volunteers are enrolled. fever, temperature > 37.0°c. have received a second covid-19 vaccine booster immunization. have a history of serious adverse reactions related to the vaccine and/or have a history of severe allergic reactions to any component of the investigational vaccine (only applicable to the vaccine groups). pregnant or lactating women. hiv infection, tuberculosis, low immunity caused by disease or long-term medication. acute disease or acute onset of chronic disease. epilepsy and other progressive neurological disorders. other situations that are not suitable for participating in this research, according to the judgment of the researcher.

volunteers have suspected symptoms of covid-19 when enrolled, such as dry throat, sore throat, cough, etc. the covid-19 antigen quick test kit is positive when volunteers are enrolled. fever, temperature > 37.0°c. have received a second covid-19 vaccine booster immunization. have a history of serious adverse reactions related to the vaccine and/or have a history of severe allergic reactions to any component of the investigational vaccine (only applicable to the vaccine groups). pregnant or lactating women. hiv infection, tuberculosis, low immunity caused by disease or long-term medication. acute disease or acute onset of chronic disease. epilepsy and other progressive neurological disorders. other situations that are not suitable for participating in this research, according to the judgment of the researcher.