inclusion criteria: 1. at the time of signing the informed consent, he was 18 years old or above; 2. normal body temperature (axillary temperature \< 37.3 ℃/oral temperature \< 37.5 ℃); 3. meet one of the following conditions: 1) 6-15 months after the basic immunization (2 injections) of the inactivated vaccine of the prototype strain of covid-19-19 has been completed; 2) 6-9 months after the booster immunization (3 injections) of the inactivated vaccine of the prototype strain of covid-19 has been completed; 3) 6-15 months after basic immunization (3 injections) of recombinant vaccine of covid-19 prototype strain has been completed. 4. the vaccines used to complete the above basic immunization or enhanced immunization were produced by beijing biotech, wuhan biotech, sinovac and zhifeilong koma, and the same kind of vaccine was inoculated throughout the whole process. 5. female subjects over 18 years old were not pregnant (blood pregnancy test was negative), were not in lactation and took effective contraceptive measures within 4 weeks after inoculation; the male subject must agree to take effective contraceptive measures by himself and his partner within 4 weeks after signing the informed consent and vaccination. 6. subjects have the ability to understand the research procedure, voluntarily sign the informed consent form after informed consent, can comply with the requirements of the clinical research protocol, and can and is willing to complete the entire required research plan.

inclusion criteria: 1. at the time of signing the informed consent, he was 18 years old or above; 2. normal body temperature (axillary temperature \< 37.3 ℃/oral temperature \< 37.5 ℃); 3. meet one of the following conditions: 1) 6-15 months after the basic immunization (2 injections) of the inactivated vaccine of the prototype strain of covid-19-19 has been completed; 2) 6-9 months after the booster immunization (3 injections) of the inactivated vaccine of the prototype strain of covid-19 has been completed; 3) 6-15 months after basic immunization (3 injections) of recombinant vaccine of covid-19 prototype strain has been completed. 4. the vaccines used to complete the above basic immunization or enhanced immunization were produced by beijing biotech, wuhan biotech, sinovac and zhifeilong koma, and the same kind of vaccine was inoculated throughout the whole process. 5. female subjects over 18 years old were not pregnant (blood pregnancy test was negative), were not in lactation and took effective contraceptive measures within 4 weeks after inoculation; the male subject must agree to take effective contraceptive measures by himself and his partner within 4 weeks after signing the informed consent and vaccination. 6. subjects have the ability to understand the research procedure, voluntarily sign the informed consent form after informed consent, can comply with the requirements of the clinical research protocol, and can and is willing to complete the entire required research plan.

inclusion criteria: at the time of signing the informed consent, he was 18 years old or above; normal body temperature (axillary temperature < 37.3 ℃/oral temperature < 37.5 ℃); meet one of the following conditions: 1) 6-15 months after the basic immunization (2 injections) of the inactivated vaccine of the prototype strain of covid-19-19 has been completed; 2) 6-9 months after the booster immunization (3 injections) of the inactivated vaccine of the prototype strain of covid-19 has been completed; 3) 6-15 months after basic immunization (3 injections) of recombinant vaccine of covid-19 prototype strain has been completed. the vaccines used to complete the above basic immunization or enhanced immunization were produced by beijing biotech, wuhan biotech, sinovac and zhifeilong koma, and the same kind of vaccine was inoculated throughout the whole process. female subjects over 18 years old were not pregnant (blood pregnancy test was negative), were not in lactation and took effective contraceptive measures within 4 weeks after inoculation; the male subject must agree to take effective contraceptive measures by himself and his partner within 4 weeks after signing the informed consent and vaccination. subjects have the ability to understand the research procedure, voluntarily sign the informed consent form after informed consent, can comply with the requirements of the clinical research protocol, and can and is willing to complete the entire required research plan.

inclusion criteria: at the time of signing the informed consent, he was 18 years old or above; normal body temperature (axillary temperature < 37.3 ℃/oral temperature < 37.5 ℃); meet one of the following conditions: 1) 6-15 months after the basic immunization (2 injections) of the inactivated vaccine of the prototype strain of covid-19-19 has been completed; 2) 6-9 months after the booster immunization (3 injections) of the inactivated vaccine of the prototype strain of covid-19 has been completed; 3) 6-15 months after basic immunization (3 injections) of recombinant vaccine of covid-19 prototype strain has been completed. the vaccines used to complete the above basic immunization or enhanced immunization were produced by beijing biotech, wuhan biotech, sinovac and zhifeilong koma, and the same kind of vaccine was inoculated throughout the whole process. female subjects over 18 years old were not pregnant (blood pregnancy test was negative), were not in lactation and took effective contraceptive measures within 4 weeks after inoculation; the male subject must agree to take effective contraceptive measures by himself and his partner within 4 weeks after signing the informed consent and vaccination. subjects have the ability to understand the research procedure, voluntarily sign the informed consent form after informed consent, can comply with the requirements of the clinical research protocol, and can and is willing to complete the entire required research plan.