A Phase III Clinical Trial of Quadrivalent Influenza Vaccine in Healthy Subjects Aged 6 to 35 Months

August 8, 2025 updated by: Sinovac Biotech Co., Ltd

An Randomized, Double-blind, Controlled Phase III Clinical Trial to Evaluate the Safety and Immunogenicity of Quadrivalent Influenza Vaccine in Healthy Subjects Aged 6 to 35months

A phase III clinical trial of the study of quadrivalent influenza vaccine developed by Sinovac Biotech will be conducted in Chinese children aged 6 to 35 months. The trial is an randomized, double-blind and active controlled study. The objective of this study is to evaluate the Immunogenicity and safety of the vaccine.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

A phase III clinical trial of the study of quadrivalent influenza vaccine developed by Sinovac Biotech will be conducted in Chinese children aged 6 to 35 months. The trial is an randomized, double-blind and active controlled study. The objective of this study is to evaluate the safety and immunogenicity of quadrivalent influenza vaccine(0.25ml and 0.5ml) manufactured by Sinovac Biotech Co., Ltd in healthy infants aged from 6 to 35 months. A total of 3300 subjects will be enrolled. The subjects will be randomly assigned to 4 groups in a 2:2:1:1 ratio and subjects will receive two doses of quadrivalent influenza vaccine(0.25ml or 0.5ml) or trivalent influenza vaccine(BV or BY), respectively, according to the immunization schedule of day 0,28 in each group.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
3300

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
    • Anhui
      • Lu'an, Anhui, China, 237400
        • Huoqiu County Center For Disease Control and Prevention
    • Hubei
      • Shiyan, Hubei, China, 442200
        • Zhushan County Center for Diseases Control and Prevention
      • Xiangyang, Hubei, China, 441500
        • Nanzhang County Center for Disease Prevention and Control
      • Xiangyang, Hubei, China, 441800
        • Laohekou Center for Disease Control and Prevention
      • Yichang, Hubei, China, 443600
        • Zigui County Center for Disease Control and Prevention

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy infants aged 6-35 months;
  • Proven vaccination certificate and birth certificate;
  • The subjects' guardians can understand and voluntarily sign the informed consent form.

Exclusion Criteria:

  • Received any circulating seasonal influenza vaccine prior to enrollment or had an influenza vaccine schedule during the study;
  • Suffering from seasonal influenza in the past 6 moths;
  • Axillary temperature >37.0°C;
  • History of allergy to the vaccine or vaccine components, or serious adverse reactions to the vaccine, such as urticaria, dyspnea, angioedema and asthma;
  • Congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.;
  • Severe chronic diseases(Such as down syndrome, diabetes, sickle cell anaemia or neurological disorders);
  • Severe neurological disease (epilepsy, convulsions or convulsions) or mental illness;
  • Autoimmune disease (such as systemic lupus erythematosus) or immunodeficiency / immunosuppression (such as HIV, after organ transplantation)
  • 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;
  • Continuous use of corticosteroids or other immunosuppressive agents for ≥ 14 days within the past 6 months (excluding allergic rhinitis corticosteroid spray therapy, acute noncomplicated dermatitis superficial corticosteroid therapy) and cytotoxic therapy in the past 6 months;
  • Acute diseases or acute exacerbation of chronic diseases in the past 3 days;
  • 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;
  • Participated in other clinical trials before enrollment and in the follow-up period, or plans to participate in other clinical trials during the clinical trial;
  • According to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Experimental Group of quadrivalent influenza vaccine(0.25ml)
1100 subjects phase III will receive two doses of quadrivalent influenza vaccine(0.25ml) according to the immunization schedule of day 0,28
Biological: Quadrivalent influenza vaccine(0.25ml)
7.5 ug hemagglutinin (HA) of each of the four influenza strains in 0.25 mL of sodium chloride, disodium hydrogen phosphate, sodium dihydrogen phosphate per njection.The routine of administration is Intramuscular injection into deltoid region.And the immunization schedule is two doses on day 0, 28.
Experimental: Experimental Group of quadrivalent influenza vaccine(0.5ml)
1100 subjects phase III will receive two doses of quadrivalent influenza vaccine(0.5ml) according to the immunization schedule of day 0,28
Biological: Quadrivalent influenza vaccine(0.5ml)
15 ug hemagglutinin (HA) of each of the four influenza strains in 0.5 mL of sodium chloride, disodium hydrogen phosphate, sodium dihydrogen phosphate per njection.The routine of administration is Intramuscular injection into deltoid region.And the immunization schedule is two doses on day 0, 28.
Active Comparator: Control Group of trivalent influenza vaccine(BV)
550 subjects phase III will receive two doses of trivalent influenza vaccine(BV) according to the immunization schedule of day 0,28.
Biological: Trivalent influenza vaccine(BV)
7.5μg inactivated influenza antigen (H1N1, H3N2, Victoria) of each of the trivalent influenza vaccine in 0.25 mL of sodium chloride, disodium hydrogen phosphate, sodium dihydrogen phosphate per injection.The routine of administration is Intramuscular injection into deltoid region. And the immunization schedule is two doses on day 0, 28.
Active Comparator: Control Group of trivalent influenza vaccine(BY)
550 subjects phase III will receive two doses of trivalent influenza vaccine(BY) according to the immunization schedule of day 0,28.
Biological: Trivalent influenza vaccine(BY)
7.5μg inactivated influenza antigen (H1N1, H3N2, and Yamagata) of each of the trivalent influenza vaccine in 0.25 mL of sodium chloride, disodium hydrogen phosphate, sodium dihydrogen phosphate per injection.The routine of administration is Intramuscular injection into deltoid region.And the immunization schedule is two doses vaccine on day 0, 28.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Seroconversion rates of HI antibody
Time Frame: 28 days after full schedule immunization
Anti-influenza antibodies were measured using HAI assay for 4 strains: H1N1, H3N2, B Victoria and B Yamagata. Seroconversion was defined as pre-vaccination titer <1：10 and post-vaccination titer ≥1:40, and Significant increase was defined as pre-vaccination titer≥1:40 and ≥ 4-fold increase of post-vaccination titer.
28 days after full schedule immunization
Geometric Mean Titers (GMTs) of HI antibody
Time Frame: 28 days after full schedule immunization
Anti-influenza antibody levels were measured using hemagglutination inhibition (HAI) assay for 4 strains: H1N1, H3N2, B Victoria, B Yamagata.
28 days after full schedule immunization
Number of Participants With Seroprotection to Influenza Vaccine Antigens
Time Frame: 28 days after full schedule immunization
Anti-influenza antibodies were measured using HAI assay for 4 strains: H1N1, H3N2, B Victoria and B Yamagata. Seroprotection was defined as an antibody titer ≥1:40 at pre-vaccination and at post-final vaccination.
28 days after full schedule immunization

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
GMIs of HI antibody
Time Frame: 28 days after full schedule immunization
Anti-influenza antibody were measured using hemagglutination inhibition (HAI) assay for 4 strains: H1N1, H3N2, B Victoria, B Yamagata. GMI is the increase fold of GMT post vaccination compared with pre vaccination
28 days after full schedule immunization
Incidence of adverse reactions
Time Frame: 0-30 days after each dose
Incidence of adverse reaction 0-30 days after each dose
0-30 days after each dose
Incidence of adverse reactions
Time Frame: 0-7 days after each dose
Incidence of adverse reaction 0-7 days after each dose
0-7 days after each dose
Incidence of Serious adverse events
Time Frame: Since the beginning of vaccination until 6 months after the last dose
Incidence of serious adverse events from beginning of vaccination until 6 months after the last dose
Since the beginning of vaccination until 6 months after the last dose
Incidence of AESI
Time Frame: since the beginning of vaccination until 6 months after the last dose
Incidence of AESI since the beginning of vaccination until 6 months after the last dose
since the beginning of vaccination until 6 months after the last dose

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Sinovac Biotech Co., Ltd

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Lei Wang, Hubei Provincial Center for Disease Prevention and Control
  • Principal Investigator: Jihai Tang, Anhui Provincial Center for Disease Prevention and Control

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 16, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 23, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 23, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 15, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 15, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 22, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 14, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 8, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • PRO-QINF-3005

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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