Study of Inactivated SARS-CoV-2 Vaccine (Vero Cells) in Healthy Population Aged 3 to 17 Years(COVID-19)

Inclusion Criteria: * Healthy residents aged 3 to 17 years at the time of consent * Subjects and/or their guardian agree to sign the informed consent forms voluntarily. * Be able to comply with study requirements/procedures. * Axillary temperature ≤ 37.0℃ Exclusion Criteria: * Within 14 days before vaccination, subjects have been abroad and to villages/communities experienced COVID-19 epidemics, and in contact with COVID-19 cases or suspected cases. Subjects are under isolation observation, or living in the villages/communities with COVID-19 cases or suspected cases; * Confirmed cases, suspected cases or asymptomatic cases with COVID-19 (refer to Information System of China Disease Prevention and Control); * Subjects with history of SARS virus infection by self-reported; * Positive in throat swab through RT-PCR; * History of vaccination of various COVID-19 vaccines or positive in SARS-CoV-2 antibody test; * Positive urine pregnancy test for females with menarche * History of severe allergic reactions (such as acute anaphylaxis, urticaria, skin eczema, dyspnea, angioneurotic edema or abdominal pain) or allergy to known composition of inactivated SARS-CoV-2 vaccine; * History or family history of convulsion, epilepsy, encephalopathy or mental illness; * Subjects with congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.; * Subjects with known or suspected diseases include: severe respiratory diseases, severe cardiovascular diseases, severe liver and kidney diseases, drug-uncontrollable hypertension, diabetic complications, malignant tumors, various acute diseases or acute onset of chronic diseases; * Diagnosed with congenital or acquired immunodeficiency, HIV infection, lymphoma, leukemia or other autoimmune diseases; * History of coagulation dysfunction (e.g. Coagulation factor deficiency, coagulation disease); * Subjects receiving anti-TB treatment; * Subjects receiving other research drugs within 6 months before vaccination; * Subjects receiving immunotherapy or inhibitor therapy within 3 months (consistently oral or infusion for more than 14 days); * Subjects receiving blood products within 3 months before administration; * Subjects vaccinated with live attenuated vaccine within 14 days before vaccination; * Subjects vaccinated with other vaccine within 7 days before vaccination; * The researchers shall judge the other conditions which might be not in compliance with the requirements of this clinical trial.