Recombinant COVID-19 Vaccine (CHO Cell, NVSI-06-09) Phase III Clinical Trial

Inclusion Criteria: Age range: healthy population aged ≥18; Judged by the investigator that the health condition is well after inquiry and physical examination; Cohort 1: participants vaccinated with ≥2 doses of inactivated COVID-19 vaccines for ≥6 months since the last dose of vaccination; Cohort 2: participants vaccinated with ≥2 doses of mRNA COVID-19 vaccines for ≥6 months since the last dose of vaccination; Be able and willing to complete all prescribed study schedules during the whole study period; The participant himself/herself is able and willing to understand study procedures, sign the informed consent form voluntarily after informed consent and comply to requirements of the study protocol. Exclusion Criteria: Symptomatic and suspected COVID 19 infection positive ; Urine pregnancy test is positive; Women of childbearing age who have positive urine pregnancy test, who are pregnant, lactating, or women who have planned pregnancy within 6 months; Auxiliary temperature before vaccination is ≥37.3℃ (tympanic/forehead temperature ≥37.8℃); Previous allergy history of vaccine vaccination (such as acute allergic reaction, urticaria, skin eczema, dyspnea, angioneurotic edema or abdominal pain, etc.) or allergy to known components of COVID-19 vaccine; Have a history of hospital-diagnosed thrombocytopenia or other coagulation disorders; With known immunological impairment or compromised immunological function diagnosed by the hospital; Received whole blood, plasma and immunoglobulin therapy within 1 month; Known or suspected of suffering from the following diseases: acute or chronic active respiratory diseases, severe cardiovascular diseases [cardiopulmonary failure, hypertension uncontrollable by drugs (systolic blood pressure ≥ 150 mmHg and/or diastolic blood pressure ≥ 95 mmHg)], acute infection, active phase of chronic disease, liver and kidney diseases, severe diabetes, malignant tumor, infectious skin diseases or severe skin allergy, HIV infection, etc. (Examination report can be provided) Received live attenuated vaccine within one month before vaccination; Received inactivated vaccine within 14 days before vaccination; Other contraindications related to vaccination that investigators believe.