Phase I Clinical Trial of Recombinant SARS-CoV-2 Spike Protein Vaccine (CHO Cell) for the Prevention of COVID-19

Inclusion Criteria:

• Healthy individuals aged 18-59 years as well as 60 years and above who can providelegal identification (males and females are both required).
• Willing to participate in the study with informed consent prior to screening
• Negative in SARS-CoV-2 IgG and IgM test at screening.
• Women of childbearing potential must be using effective method of birth control for 14days prior to the enrollment of the study vaccine/placebo and must agree to continuesuch precautions during the study until 30 days after the second dose of the studyvaccine/placebo.
• Male subjects must agree to employ acceptable contraception from the day of first doseof the study vaccine/placebo until 30 days after the second dose of the studyvaccine/placebo.

Exclusion Criteria:

• Confirmed or asymptomatic COVID-19 cases or SARS-CoV-2 infection(had positive inSARS-CoV-2 nucleic acid test or serological test).
• Had a history of traveling or residence in domestic area of high and moderate pandemicrisk, overseas or epidemic areas, or had a history of contact with confirmed,asymptomatic or suspected COVID-19 cases within the past 14 days;
• History of SARS;
• Received SARS-CoV-2 vaccines for emergency use or approved SARS-CoV-2 vaccines;
• Individuals involving a clinical study within 6 months prior to the screening visit;or planning to participate in another clinical study during study period.
• Clinical laboratory abnormalities and with clinical significance judged byinvestigator
• Individual's systolic blood pressure ≥ 150mmHg and/or diastolic blood pressure ≥ 100mmHg at screening visit
• Axillary temperature >=37.3℃ prior to vaccination
• Individuals in other acute diseases, or in the acute phase of chronic diseases within 3 days prior to the signing of the informed consent form.
• Received immunoglobulin and/or blood product 3 months prior to the first vaccination.
• Presence of uncontrolled chronic pulmonary, cardiovascular, renal, hepatic,neurologic, hematologic or metabolic (including diabetes mellitus) disorders, whichwould include the potential subject in a high-risk category for SARS-CoV-2 infectionand/or its complications as judged by the investigator..
• Individuals with a history of severe allergic reaction (throat swelling, difficult inbreath, dyspnea, or shock).
• Individuals who have a history of severe adverse reaction associated with a vaccine orsevere allergic reaction [e.g., anaphylaxis to any component of the study vaccines (Sprotein, Aluminum hydroxide, CpG adjuvant).
• Any autoimmune or immunodeficiency disease/condition [e.g. human immunodeficiencyvirus (HIV) infection, Systemic lupus erythematosus (SLE)]
• Received immunoglobulin, blood-derived products within 3 months prior to the firststudy vaccination.
• Abnormal coagulation function (such as coagulation factor deficiency, coagulationdisease, platelet abnormality) obvious bruises or coagulopathy.
• Pregnant women or breastfeeding women.
• According to the judgment of the investigator, subject has or had any other symptoms,medical history and other factors that are not suitable for participating in thisclinical trial.