Safety and Immunogenicity Study of Inactivated Vaccine for Prevention of COVID-19

Inclusion Criteria:

- Healthy children and adolescents aged 3-17 years;

- The subject and/or guardian can understand and voluntarily sign the informed consent
form (double sign required for 8-17 years old);

- Proven legal identity.

Exclusion Criteria:

- Travel history / residence history of communities with case reports within 14 days;

- History of contact with a SARS-CoV-2 infection (positive in nucleic acid test) within
14 days;

- Have contacted patients with fever or respiratory symptoms from communities with case
reports within 14 days;

- Two or more cases of fever and / or respiratory symptoms in a small contact area of
volunteers, such as home, office etc. within 14 days;

- History of SARS-CoV-2 infection;

- 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 or immunodeficiency / immunosuppression;

- 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, spleenlessness, functional
spleenlessness, spleenlessness or splenectomy resulting from any condition;

- 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;

- Physical examination has clinically significant abnormal hematology and biochemistry
laboratory test results that exceed the reference value range (only applicable to
phase I clinical trials):

1. Blood routine test: white blood cell count, hemoglobin, platelet count;

2. Detection of blood biochemical indicators: alanine aminotransferase (ALT),
aspartate aminotransferase (AST), total bilirubin (TBIL), creatinine (CR),
fasting blood glucose;

3. Urine routine index: urine protein (PRO);

- History of alcohol or drug abuse;

- 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;

- Acute diseases or acute exacerbation of chronic diseases in the past 7 days;

- Axillary temperature >37.0°C;

- Already pregnant (including a positive urine pregnancy test) or are breastfeeding,
planning to get pregnant within 3 months;

- According to the investigator's judgment, the subject has any other factors that are
not suitable for participating in the clinical trial.