Seasonal InfluenzaPhase 3NCT06049927

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

A Phase 3 study testing Quadrivalent influenza vaccine(0.25ml), Quadrivalent influenza vaccine(0.5ml) and Trivalent influenza vaccine(BV) in people with Seasonal Influenza, run by Sinovac Biotech Co., Ltd at 5 sites in China.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

Who is it for?: Ages 6 to 35 monthsHealthy volunteers can take part
Conditions the study is for: Seasonal Influenza
What is being tested?: Quadrivalent influenza vaccine(0.25ml), Quadrivalent influenza vaccine(0.5ml) and Trivalent influenza vaccine(BV)
Type of treatment: Vaccines, Injection or infusion
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 3,300 participants
Where: 5 sitesChina
Study dates: 16 Sep 2023to 23 May 2024
Phase: Phase 3

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 6 to 35 months
All sexes
Healthy volunteers accepted
Child

Who may be able to join

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

Who cannot join

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);

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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

Trial locations and contacts

5 sites in 1 country.

City, postcode or hospital

5 sites in 1 country

China5 sites

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

Other trials in China

About this study

Official title: 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

Read the 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.

Conditions: Seasonal Influenza
Being tested: Quadrivalent influenza vaccine(0.25ml), Quadrivalent influenza vaccine(0.5ml), Trivalent influenza vaccine(BV), Trivalent influenza vaccine(BY)

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Quadrivalent influenza vaccine(0.25ml)Biological
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.
Quadrivalent influenza vaccine(0.5ml)Biological
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.
Trivalent influenza vaccine(BV)Biological
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.
Trivalent influenza vaccine(BY)Biological
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.

Study groups in NCT06049927
Study group	Role	What they receive
Experimental Group of quadrivalent influenza vaccine(0.25ml)	Experimental	1100 subjects phase III will receive two doses of quadrivalent influenza vaccine(0.25ml) according to the immunization schedule of day 0,28 Receives: Biological: Quadrivalent influenza vaccine(0.25ml)
Experimental Group of quadrivalent influenza vaccine(0.5ml)	Experimental	1100 subjects phase III will receive two doses of quadrivalent influenza vaccine(0.5ml) according to the immunization schedule of day 0,28 Receives: Biological: Quadrivalent influenza vaccine(0.5ml)
Control Group of trivalent influenza vaccine(BV)	Active comparator	550 subjects phase III will receive two doses of trivalent influenza vaccine(BV) according to the immunization schedule of day 0,28. Receives: Biological: Trivalent influenza vaccine(BV)
Control Group of trivalent influenza vaccine(BY)	Active comparator	550 subjects phase III will receive two doses of trivalent influenza vaccine(BY) according to the immunization schedule of day 0,28. Receives: Biological: Trivalent influenza vaccine(BY)

What is being measured

The primary outcome is the main question the study is designed to answer.

Seroconversion rates of HI antibody
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.
Measured: 28 days after full schedule immunization
Geometric Mean Titers (GMTs) of HI antibody
Anti-influenza antibody levels were measured using hemagglutination inhibition (HAI) assay for 4 strains: H1N1, H3N2, B Victoria, B Yamagata.
Measured: 28 days after full schedule immunization
Number of Participants With Seroprotection to Influenza Vaccine Antigens
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.
Measured: 28 days after full schedule immunization

Secondary outcomes (5)

GMIs of HI antibody
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
Measured: 28 days after full schedule immunization
Incidence of adverse reactions
Incidence of adverse reaction 0-30 days after each dose
Measured: 0-30 days after each dose
Incidence of adverse reactions
Incidence of adverse reaction 0-7 days after each dose
Measured: 0-7 days after each dose
Incidence of Serious adverse events
Incidence of serious adverse events from beginning of vaccination until 6 months after the last dose
Measured: Since the beginning of vaccination until 6 months after the last dose
Incidence of AESI
Incidence of AESI since the beginning of vaccination until 6 months after the last dose
Measured: since the beginning of vaccination until 6 months after the last dose

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

16 Sep 202323 May 2024

First posted22 Sep 2023
Study start16 Sep 2023
Primary completion23 May 2024
Study completion23 May 2024

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Publications (1)Papers the sponsor has linked to this study.
Other trials for Seasonal InfluenzaStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 3
Primary purpose: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: Quadruple blind
Who is masked: Participant, Care provider, Investigator, Outcomes assessor
Enrolment: 3,300 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT06049927
Sponsor's protocol ID: PRO-QINF-3005
Status last verified: Aug 2025
First submitted: 15 Sep 2023
Last updated: 14 Aug 2025
Results posted: No
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No

Publications

Wang L, Li L, Yang W, Pang X, Li D, Zhu T, Wang S, Li T, Tian Y, Jiang Z, Li J, Yang X, Zhao C, Tang J, Tong Y. Immunogenicity and safety of inactivated quadrivalent influenza vaccines in children aged 6-35 months: A multi-center, randomized, double-blind, active-controlled clinical trial. Vaccine. 2026 Jan 25;71:128113. doi: 10.1016/j.vaccine.2025.128113. Epub 2025 Dec 13.
PubMed 41391373

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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