Safety and Immunogenicity Study of Inactivated Vaccine for Prevention of COVID-19
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ClinicalTrials.gov Identifier: NCT04551547 |
Recruitment Status :
Active, not recruiting
First Posted : September 16, 2020
Last Update Posted : April 20, 2022
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Condition or disease | Intervention/treatment | Phase |
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COVID-19 | Biological: Two doses of low dosage inactivated SARS-CoV-2 vaccine at the schedule of day 0,28 Biological: Two doses of medium dosage inactivated SARS-CoV-2 vaccine at the schedule of day 0,28 Other: Two doses of placebo at the schedule of day 0,28 | Phase 1 Phase 2 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 552 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Double (Participant, Investigator) |
Primary Purpose: | Prevention |
Official Title: | A Randomized, Double-Blinded, Placebo-Controlled, Phase Ⅰ/Ⅱ Clinical Trial, to Evaluate the Safety and Immunogenicity of the SARS-CoV-2 Inactivated Vaccine (Vero Cell) in Healthy Population Aged 3-17 Years |
Actual Study Start Date : | October 31, 2020 |
Actual Primary Completion Date : | April 30, 2021 |
Estimated Study Completion Date : | September 2022 |

Arm | Intervention/treatment |
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Experimental: Experimental Vaccine-low dosage
low dosage inactivated SARS-CoV-2 vaccine
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Biological: Two doses of low dosage inactivated SARS-CoV-2 vaccine at the schedule of day 0,28
The inactivated SARS-CoV-2 vaccine was manufactured by Sinovac Research & Development Co., Ltd., with a antigen content of 300SU/0.5ml |
Experimental: Experimental Vaccine-medium dosage
medium dosage inactivated SARS-CoV-2 vaccine
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Biological: Two doses of medium dosage inactivated SARS-CoV-2 vaccine at the schedule of day 0,28
The inactivated SARS-CoV-2 vaccine was manufactured by Sinovac Research & Development Co., Ltd., with a antigen content of 600SU/0.5ml |
Placebo Comparator: Placebo
No active ingredient in the placebo
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Other: Two doses of placebo at the schedule of day 0,28
The placebo contains no active ingredient and manufactured by Sinovac Research & Development Co., Ltd. |
- Safety index-incidence of adverse reactions [ Time Frame: Day 0-28 after each dose vaccination ]Incidence of adverse reactions after each dose vaccination.
- Immunogenicity index-seroconversion rates of neutralizing antibody [ Time Frame: The 28th day after the second dose vaccination ]Neutralizing antibody assay will be performed using the micro-neutralization method. Seroconversion will be defined as a change from seronegative (<1:8) to seropositive (≥1:8), or ≥4 fold increase from baseline.
- Safety index-incidence of serious adverse events [ Time Frame: From the beginning of the vaccination to 12 months after the second dose vaccination ]SAE will be collected throughout the clinical trial.
- Immunogenicity index-seropositive rates of neutralizing antibody [ Time Frame: The 28th day after each dose vaccination and the 12 month after the second dose vaccination ]Neutralizing antibody assay will be performed using the micro-neutralization method, and subjects with a antibody titer ≥1:8 will defined as seropositive.
- Immunogenicity index-geometric mean titer (GMT) of neutralizing antibody [ Time Frame: The 28th day after each dose vaccination and the 12 month after the second dose vaccination ]Neutralizing antibody assay will be performed using the micro-neutralization method.
- Immunogenicity index-geometric mean ratio (GMR) of neutralizing antibody [ Time Frame: The 28th day after each dose vaccination and the 12 month after the second dose vaccination ]Neutralizing antibody assay will be performed using the micro-neutralization method. Ratio of post-vaccination titer divided by baseline titer will be calculated.
- Safety index-Incidence rate of adverse reactions [ Time Frame: Within 7 days after each dose vaccination ]Incidence rate of adverse reactions within 7 days after each dose vaccination
- Safety index-Incidence of abnormal laboratory index [ Time Frame: On the 3th day after each dose of vaccination in phase Ⅰ ]Incidence of abnormal laboratory index (blood routine test, blood chemistry test, and urine routine test) on the 3th day after each dose of vaccination in phase Ⅰ
- Safety index-Incidence rate of AESIs [ Time Frame: From the beginning of the vaccination to 12 months after the last dose vaccination ]Incidence rate of SAEs and AESIs from the beginning of the vaccination to 12 months after the last dose vaccination
- Immunogenicity index- GMI of neutralizing antibody [ Time Frame: 28 days after the second dose vaccination ]GMI of neutralizing antibodies 28 days after the second dose vaccination
- Immunogenicity index-the seroconversion rate [ Time Frame: 28 days after the first dose vaccination in phase Ⅰ ]The seroconversion rate 28 days after the first dose vaccination in phase Ⅰ
- Immunogenicity index-the seropositive rate [ Time Frame: 28 days after the first dose vaccination in phase Ⅰ ]Seropositive rate 28 days after the first dose vaccination in phase Ⅰ
- Immunogenicity index-the GMT [ Time Frame: 28 days after the first dose vaccination in phase Ⅰ ]The GMT 28 days after the first dose vaccination in phase Ⅰ
- Immunogenicity index-the GMI [ Time Frame: 28 days after the first dose vaccination in phase Ⅰ ]The GMI 28 days after the first dose vaccination in phase Ⅰ
- Phase Ⅰ: The seropositive rate of neutralizing antibody [ Time Frame: 6 months and 12 months after the second dose vaccination ]The seropositive rate of neutralizing antibody against live SARS-CoV-2 6 months and 12 months after the second dose vaccination
- Phase Ⅰ:The GMT of neutralizing antibody [ Time Frame: 6 months and 12 months after the second dose vaccination. ]The GMT of neutralizing antibody against live SARS-CoV-2 6 months and 12 months after the second dose vaccination.
- Phase Ⅱ: The seropositive rate of neutralizing antibody [ Time Frame: 3 months, 6 months, 9 months and 12 months after the second dose vaccination ]The seropositive rate of neutralizing antibody against live SARS-CoV-2 3 months, 6 months, 9 months and 12 months after the second dose vaccination
- Phase Ⅱ: The GMT of neutralizing antibody [ Time Frame: 3 months, 6 months, 9 months and 12 months after the second dose vaccination. ]The GMT of neutralizing antibody against live SARS-CoV-2 3 months, 6 months, 9 months and 12 months after the second dose vaccination.
- Phase Ⅱ: The seropositive rate [ Time Frame: 28 days after the booster dose ]The seropositive rate of neutralizing antibody against Prototype SARS-CoV-2 and Omicron strain 28 days after the booster dose
- Phase Ⅱ: The GMT [ Time Frame: 28 days after the booster dose ]The GMT of neutralizing antibody against Prototype SARS-CoV-2 and Omicron strain 28 days after the booster dose
- Phase Ⅱ: The GMI [ Time Frame: 28 days after the booster dose ]The GMI of neutralizing antibody against Prototype SARS-CoV-2 and Omicron strain 28 days after the booster dose
- Phase Ⅱ: the seropositive rate [ Time Frame: 6 months and 12 months after the booster dose ]The seropositive rate of neutralizing antibody against Prototype SARS-CoV-2 and Omicron strain 6 months and 12 months after the booster dose.
- Phase Ⅱ: the GMT [ Time Frame: 6 months and 12 months after the booster dose ]The GMT of neutralizing antibody against Prototype SARS-CoV-2 and Omicron strain 6 months and 12 months after the booster dose.

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Ages Eligible for Study: | 3 Years to 17 Years (Child) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
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;
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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):
- Blood routine test: white blood cell count, hemoglobin, platelet count;
- Detection of blood biochemical indicators: alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), creatinine (CR), fasting blood glucose;
- 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.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04551547
China, Hebei | |
Zanhuang county Center for Disease Control and Prevention | |
Shijiazhuang, Hebei, China, 051230 |
Principal Investigator: | Yuliang Zhao, Master | Hubei Provincial Center for Disease Control and Prevention |
Responsible Party: | Sinovac Research and Development Co., Ltd. |
ClinicalTrials.gov Identifier: | NCT04551547 |
Other Study ID Numbers: |
PRO-nCOV-1003 |
First Posted: | September 16, 2020 Key Record Dates |
Last Update Posted: | April 20, 2022 |
Last Verified: | June 2021 |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
COVID-19 Respiratory Tract Infections Infections Pneumonia, Viral Pneumonia Virus Diseases Coronavirus Infections Coronaviridae Infections |
Nidovirales Infections RNA Virus Infections Lung Diseases Respiratory Tract Diseases Vaccines Immunologic Factors Physiological Effects of Drugs |