safety and immunogenicity study of booster vaccination with covid-19 vaccine (vero cell),inactivated from different manufactures for prevention of covid-19

Conditions: COVID-19

Summary: this is a randomized, open, control phase ⅳ clinical trial of inactivated covid-19 vaccine manufactured by sinovac research \& development co., ltd,beijing institute of biological products co.,ltd and wuhan institute of biological products co.,ltd.the purpose of this study is to explore booster immunization of sars-cov-2 inactivated vaccine from different manufactures in adults aged 18-45 years old previously vaccinated with inactivated covid-19 vaccine

this study a randomized, open, control phase ⅳclinical trial of inactivated covid-19 vaccine .the purpose of this study is to explore booster immunization of sars-cov-2 inactivated vaccine from different manufactures in adults aged 18-45 years old previously vaccinated with inactivated covid-19 vaccine.a total of 480 subjects who have completed vaccination of two doses of inactivated covid-19 vaccine for 6 to 8 months will be enrolled.in this study ,96 subjects who completed primary immunization with inactivated covid-19 vaccine manufactured by sinovac research \& development co.,ltd. will receive one dose of booster immunization with inactivated covid-19 vaccine manufactured by sinovac research \& development co.,ltd.(experimental group 1).192 subjects who completed primary immunization with inactivated covid-19 vaccine manufactured by beijing institute of biological products co.,ltd. will be randomly divided into two groups (experimental group 2 and experimental group 3) in a 1:1 ratio and receive one dose of booster immunization with inactivated covid-19 vaccine manufactured by sinovac research \& development co.,ltd. and beijing institute of biological products co., ltd,respectively.192 subjects who completed primary immunization with inactivated covid-19 vaccine manufactured by wuhan institute of biological products co.,ltd.will be randomly divided into two groups(experimental group 4 and experimental group 5) in a 1:1 ratio and receive one dose of booster immunization with inactivated covid-19 vaccine manufactured by sinovac research \& development co.,ltd. and wuhan institute of biological products co.,ltd.

Eligibility criteria:
inclusion criteria: * adults aged 18-45; * proven legal identity; * the subjects can understand and voluntarily sign the informed consent form and be willing to complete the study in accordance with the study plan; * have completed two doses of sars-cov-2 inactivated vaccine vaccination for 6 to 8 months(the interval between the two doses vaccine of primary immunization is 21\~35 days, and the two doses vaccine of primary immunization should be manufactured by the same manufactures). exclusion criteria: * history of sars-cov-2 infection(laboratory confirmed); * have received inactivated sars-cov-2 vaccine from other manufacturers other than sinovac life sciences co., ltd.,beijing institute of biological products co.,ltd.and wuhan institute of biological products co.,ltd.and received three and more doses of inactivated sars-cov-2 vaccine; * severe adverse reactions, such as urticaria, dyspnea, and angioneurotic edema , occurred during the primary immunization; * autoimmune disease such as systemic lupus erythematosus or immunodeficiency / immunosuppression such as aids, post-transplant; * 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; * 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; * 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 other investigational drugs in the past 30 days; * receipt of attenuated live vaccines in the past 14 days; * acute diseases or acute exacerbation of chronic diseases within 7 days prior to booster vaccination; * axillary temperature \>37.0°c; * already pregnant or are breastfeeding, planning to get pregnant within 1months (according to subjects' self-report and urine pregnancy test results); * participated in other clinical trials prior to enrollment and during the followup period, or planned to participate in other clinical trials during the clinical trial period; * according to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial.