lot-to-lot consistency of an inactivated sars-cov-2 vaccine between different workshops in healthy children aged 3-17 years

Conditions: COVID-19

Summary: this study is a double-blind, randomized phase ⅳ clinical trial of the inactivated sars-cov-2 vaccine (coronavac)manufactured by sinovac research \& development co., ltd. the purpose of this study is to evaluate the lot-to-lot consistency ,immunogenicity and safety of covid-19 vaccine between the commercialized scale in workshop 2 and 3 and the commercialized scale in workshop 1 in healthy children aged 3-17 years.

this study is a double-blind, randomized phase ⅳ clinical trial in healthy children aged 3-17 years to evaluate the lot-to-lot consistency, immunogenicity and safety of the commercial-scale coronavac in healthy children aged 3-17 years .the experimental vaccine was manufactured by sinovac research \& development co.,ltd. a total of 2520 healthy subjects aged 3 to 17 years old will be enrolled.the subjects will be randomly divided into 7 groups of 360 participants per group with an equal probability to received 7 batches of commercial-scale vaccine.all subjects received two doses of vaccine on day 0 and day 28.

Eligibility criteria:
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.