Phase I Trial of a Recombinant COVID-19 Vaccine (CHO Cell)

Inclusion Criteria: * Healthy subjects of ≥ 18 years old. * The subject can understand and voluntarily sign the informed consent. * The subject can The subject canprovide legal identification. Exclusion Criteria: * Have a history of close contact with a confirmed case of SARS-CoV-2, an asymptomatic infection in the previous 14 days, or a travel history/residential history in a community where a case has been reported. * Have a history of contact with a person infected with SARS-CoV-2(a person with a positive nucleic acid test) in the previous 14 days. * Patients with fever or respiratory symptoms who have been to middle or high-risk areas in the past 14 days or have exit history, or come from communities with case reports. * In the past 14 days, there have been 2 or more cases of fever and/or respiratory symptoms in small areas such as homes, offices, school classes, etc. * Have a history of SARS. * Have a history of SARS-CoV-2 infection. * Positive in SARS-CoV-2 IgG or IgM antibody screening. * Positive in RT-PCR test of SARS-CoV-2 in throat swab. * Positive in HIVantibody screening. * Women who are breastfeeding, pregnant, or planning to become pregnant during the study period (based on the subject's self-report and blood pregnancy test results for women of childbearing age), or men who plan to conceive their partners during the study period. * Subjects with body mass index (BMI) ≥35 kg/m2. * Have a history of asthma, a history of vaccine or vaccine component allergy, have serious adverse reactions to the vaccine, such as urticaria, dyspnea, angioedema. * Subjects with congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc. * Subjects with autoimmune diseases or immunodeficiency/immunosuppression. * Subjects with severe chronic diseases, severe cardiovascular diseases, hypertension and diabetes that cannot be controlled by drugs, liver and kidney diseases, malignant tumors, etc. * Subjects with severe neurological disease (epilepsy, convulsions or convulsions) or mental illness. * Subjects with thyroid disease or history of thyroidectomy, no spleen, functional asthenia, and any spleen or splenectomy caused by any condition. * Abnormal blood coagulation function diagnosed by a doctor (such as coagulation factor deficiency, coagulopathy, abnormal platelet) or obvious bruise or coagulation disorder. * Have received immunosuppressant therapy, cytotoxic therapy, and inhaled corticosteroids in the past 6 months (excluding corticosteroid spray therapy for allergic rhinitis and surface corticosteroid therapy for acute non-complicated dermatitis). * Physical examination or chest CT imaging reveals clinically significant abnormalities. * Abnormal laboratory test results such as hematology and biochemistry that are beyond the reference value range and have clinical significance. 1. Routine blood test: white blood cell count, hemoglobin, platelet count. 2. Blood biochemical index detection: alanine aminotransferase (ALT), aspartate aminotransferase (AST), fasting blood glucose, C-reactive protein, total bilirubin (TBIL), creatinine (CR), creatine phosphokinase (CPK). 3. Urine routine indicators: urine protein (PRO), urine sugar, urine red blood cells. 4. Coagulation function test: prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (FIB). * Have a long history of alcohol or drug abuse. * Received blood products within 3 months before receiving trial vaccine. * Received other study drugs within 30 days before receiving the trail vaccine. * Received a live attenuated vaccine within 14 days before receiving the experimental vaccine. * Received a subunit or inactivated vaccine within 7 days before receiving the experimental vaccine. * Various acute or chronic diseases occurred in the past 7 days. * Axillary body temperature\>37.0℃ before vaccination. * According to the judgment of the investigator, the subject has any other factors that are not suitable for participating in the clinical trial. Exclusion criteria of subsequent dose: If one of the following (1) to (4) adverse events (AE) occurs, the vaccination is prohibited, but other research steps can be continued according to the investigator's judgment; if one of the following (5), (6) adverse events occurs , The investigator will judge whether to inoculate; if one of the following events (7) to (10) occurs, the vaccination can be postponed within the time window specified in the plan. * (1)The subjects used the same vaccine other than the experimental vaccine during the study. * (2)Any serious adverse reactions that are causally related to vaccination. * (3)Severe allergic or hypersensitivity reactions after vaccination (including urticaria/skin rash within 30 minutes after vaccination). * (4)Any confirmed or suspected autoimmune disease or immunodeficiency disease, including human immunodeficiency virus (HIV) infection. * (5)Acute or new-onset chronic disease after vaccination. * (6)Other reactions (including severe pain, severe swelling, severe activity limitation, persistent high fever, severe headache, or other systemic or local reactions) are judged by the investigator. * (7)Acute illness at the time of vaccination (Acute illness refers to moderate or severe illness with or without fever). * (8)Axillary temperature \>37.0℃ before vaccination. * (9)Vaccination of subunit vaccine or inactivated vaccine within 7 days, live attenuated vaccine within 14 days. * (10)According to the investigator's judgment, the subject has any other factors that are not suitable for vaccination.