Inclusion Criteria:  Healthy children aged 3-17; The subjects and/or guardians can understand and voluntarily sign the informed consent form (For subjects aged 8-17 years, both subjects and guardians need to sign the informed consent form) Proven legal identity.  Exclusion Criteria:  History of SARS-CoV-2 infection; History of receiving COVID-19 vaccine; History of asthma, history of allergy to the vaccine or vaccine components, or serious adverse reactions to the vaccine, such as urticaria, dyspnea,and angioedema; Congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.; Autoimmune disease (Systemic lupus erythematosus)or immunodeficiency / immunosuppression(HIV,history after organ transplantation) Severe chronic diseases, severe cardiovascular diseases, hypertension and diabetes that cannot be controlled by drugs, liver or kidney diseases, malignant tumors, etc.; Severe neurological disease (epilepsy, convulsions or convulsions) or mental illness; Thyroid disease or history of thyroidectomy,absence of spleen, functional absence of spleen, absence of spleen due to any condition or splenectomy; Diagnosed abnormal blood coagulation function (eg, lack of blood coagulation factors, blood coagulopathy, abnormal platelets) or obvious bruising or blood coagulation; Immunosuppressive therapy, cytotoxic therapy, inhaled corticosteroids (excluding allergic rhinitis corticosteroid spray therapy, acute noncomplicated dermatitis superficial corticosteroid therapy) in the past 6 months; Receipt of blood products within in the past 3 months; Receipt of other investigational drugs in the past 30 days; Receipt of attenuated live vaccines in the past 14 days; Receipt of inactivated or subunit vaccines in the past 7 days; Onset of various acute or chronic diseases within 7 days prior to the study; Axillary temperature >37.0°C; The subjects participated in other clinical trials during the follow-up period, or will be planned within 3 months; Already pregnant (including a positive urine pregnancy test) or are breastfeeding, planning to get pregnant within 2 months; According to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial.