safety and immunogenicity study of inactivated vaccine for prevention of sars-cov-2 infection(covid-19)

Conditions: COVID-19

Summary: this study is a randomized, double-blinded, and placebo controlled phase 1\&2 clinical trial of the sars-cov-2 inactivated vaccine manufactured by sinovac life sciences co. , ltd. the purpose of this study is to evaluate the safety and immunogenicity of the experimental vaccine in healthy elderly aged 60 years and above.

this study is a randomized, double-blinded, single-center, placebo-controlled phase 1\&2 clinical trial in healthy elderly aged 60 years and above. the experimental vaccine and placebo were both manufactured by sinovac life sciences co. , ltd. a total of 422 subjects will be enrolled, with 72 in phase 1 and 350 in phase 2. 72 subjects with 36 in medium-dosage group and 36 in high-dosage group in phase 1 will receive two doses of primary immunization according to the immunization schedule of day 0, 28 and the subjects at each dosage group will be assigned in a 2:1 ratio to receive investigational vaccine or placebo respectively.all enrolled subjects will receive 1 dose of booster immunization 1 year after primary immunization.350 subjects in phase 2 will receive two doses of primary immunization according to the immunization schedule of day 0,28,the subjects will be assigned in a ratio of 2:2:2:1 to receive the low dosage, medium dosage, high dosage vaccine, or placebo. all enrolled subjects will received 1 dose of booster immunization(the third dose ) 6 months after primary immunization.and subjects in medium-dosage group and high -dosage group will receive the second booster dose (the fourth dose) 1 year after the second dose.

Eligibility criteria:
inclusion criteria: * healthy adults aged ≥60 years; * be able to understand and sign the informed consent voluntarily; * provide legal identification; exclusion criteria: * travel / residence history of wuhan city and surrounding areas or other communities with case reports within 14 days prior to the enrolment; * contact with sars-cov-2 infected persons (positive for nucleic acid detection) within 14 days prior to the enrolment; * contact patients with fever or respiratory symptoms from wuhan city and surrounding areas, or from communities with case reports within 14 days prior to the enrolment; * two or more cases of fever and / or respiratory symptoms in a small contact area of subjects, such as family, office, school class or other places within 14 days prior to the enrolment; * history of sars; * history of sars-cov-2 infection; * history of asthma, allergy to vaccines or vaccine ingredients, and serious adverse reactions to vaccines, such as urticaria, dyspnea, angioneuroedema; * congenital malformation or developmental disorder, genetic defect, severe malnutrition, etc; * autoimmune disease or immunodeficiency / immunosuppression; * serious chronic disease, serious cardiovascular disease, hypertension and diabetes that cannot be controlled by drugs, hepatorenal disease, malignant tumor, etc; * serious nervous system disease (epilepsy, convulsion or convulsion) or psychosis; * thyroid disease or history of thyroidectomy, asplenia, functional asplenia, asplenia 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 non-complicated dermatitis superficial corticosteroid therapy) in the past 6 months; * long history of alcohol or drug abuse; * receipt of blood products 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; * according to the investigator's judgment, the subject has any other factors that are not suitable for the clinical trial.