InfluenzaPhase 4NCT07854392

A Study to Evaluate the Immune Responses of Subunit Influenza Vaccine in Healthy Adults

A Phase 4 study testing Group A and Group B in people with Influenza, run by Ab&B Bio-tech Co., Ltd.JS at 1 site in China.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record

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Trial summary

Who is it for?: Ages 18 to 59 yearsHealthy volunteers can take part
Conditions the study is for: Influenza
What is being tested?: Group A and Group B
Type of treatment: Vaccines
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 138 participants
Where: 1 siteChina
Study dates: 10 Oct 2026to 11 Oct 2027
Phase: Phase 4
Are there results?: Not yet: the study is under way

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 18 to 59 years
All sexes
Healthy volunteers accepted
Adult

Who may be able to join

Adults aged between 18 and 59 years at the time of informed consent signature.
Judged by the investigator to be in good health, based on medical history and physical examination findings obtained at screening.
Able to comprehend and voluntarily provide written informed consent, and willing to comply with all study procedures and requirements.

Who cannot join

Known allergy to any component of the vaccine, including excipients, formaldehyde, or Triton N-101.
Confirmed influenza infection or influenza-like illness within the past 6 months, or close contact with a confirmed influenza case within 14 days prior to the screening visit.
Receipt of any influenza vaccine (licensed or investigational) within the past 6 months.
Receipt of any licensed vaccine within 28 days prior to study vaccination, or planned receipt of any licensed vaccine within 28 days after study vaccination.
Receipt of blood products or immunoglobulin within the past 3 months, or planned receipt within 1 month after study vaccination.
Female participants who are known to be pregnant or breastfeeding; female participants of childbearing potential with a positive pregnancy test at screening; or those planning pregnancy within the next 3 months.

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Presence of acute illness, acute exacerbation of a chronic disease, or fever (axillary temperature ≥37.3 °C) within 3 days prior to vaccination. Use of anti-inflammatory, antibiotic, anti-allergic, or antiviral medications within 3 days prior to vaccination due to illness, including but not limited to acetaminophen, ibuprofen, loratadine, penicillins, cephalosporins, ribavirin, oseltamivir, and acyclovir.
Systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg on the day of vaccination.
Severe chronic cardiovascular or pulmonary disease:
Heart failure with a history of acute exacerbation within the past 2 years;
Chronic obstructive pulmonary disease (COPD) with a history of acute exacerbation within the past 2 years;
Chronic interstitial lung disease with acute exacerbation or requirement for treatment adjustment within the past 2 years;
- History of asthma exacerbation within the past 2 years, or worsening asthma symptoms requiring adjustment of controller medication within the past 2 months;
Uncontrolled serious arrhythmia, or hospitalization for acute arrhythmia or regular antiarrhythmic medication within the past 6 months;
Unstable coronary artery disease within the past 3 months, as evidenced by percutaneous coronary intervention (e.g., stent implantation), coronary artery bypass grafting (CABG), newly initiated cardiac medication for symptom control, or unstable angina.
Uncontrolled epilepsy or other progressive neurological diseases (e.g., multiple sclerosis, dementia, Parkinson's disease, neurodegenerative disorders, neuropathy); History of Guillain-Barré syndrome; Stroke with residual neurological deficits within the past 12 months; Any other neurological disease with residual symptoms within the past 12 months.
Currently receiving anti-tumor therapy, including chemotherapy/radiotherapy, targeted therapy, or immunotherapy; Recurrence or metastasis of malignancy within the past 12 months; History of solid organ transplantation or hematopoietic stem cell transplantation.
Chronic conditions potentially affecting study outcomes:
Diagnosed hypertension or diabetes mellitus;
Symptoms of myocarditis or pericarditis;
Anemia, thrombocytopenia, or other coagulation disorders;
Gout with joint redness and swelling, or use of systemic corticosteroids, high-dose colchicine, or non-steroidal anti-inflammatory drugs (NSAIDs) within the past month;
Autoimmune diseases (e.g., systemic lupus erythematosus, rheumatoid arthritis, systemic vasculitis);
Severe immunodeficiency, or requirement for immunosuppressive or corticosteroid therapy during the study period, or any medical history associated with impaired immunity (e.g., HIV infection, malignancy, particularly leukemia or lymphoma, history of radiation therapy, or use of immunosuppressive or anti-neoplastic agents);
Chronic kidney disease/renal insufficiency, or chronic gastrointestinal and hepatic diseases (e.g., chronic gastritis, irritable bowel syndrome [IBS], inflammatory bowel disease [IBD], Crohn's disease, colitis, hepatitis B, hepatitis C, non-alcoholic fatty liver disease, cirrhosis, hepatocellular carcinoma) requiring regular medication;
Uncontrolled allergic diseases (e.g., allergic asthma, allergic rhinitis). Presence of active, unhealed systemic or extensive cutaneous allergic conditions at screening, including but not limited to allergic dermatitis, severe eczema, urticaria, acute flare of psoriasis, or exfoliative dermatitis. Frequent episodes of unexplained pruritus, rash, or wheals within the past month, or unstable skin allergic conditions requiring continuous antihistamine therapy, as judged by the investigator to make the participant unsuitable for enrollment.
Planned relocation outside the study site area before completion of all study procedures, or anticipated prolonged absence during scheduled follow-up visits that would prevent completion of the study schedule.
Currently enrolled in any other clinical trial, or planning to participate in another clinical trial before completion of the present study.
Any other condition or circumstance that, in the investigator's opinion, renders the participant unsuitable for enrollment.

Trial locations and contacts

1 site in 1 country.

China1 site

Shangyu District Center for Disease Control and Prevention
Shaoxing, Zhejiang, 312000

Other trials in China

About this study

Official title: A Phase IV, Prospective, Open-label, Parallel Time-cohort Study to Evaluate the Immune Responses and Safety ofSubunit Influenza Vaccine in Healthy Adults

This is a prospective, open-label, parallel time-cohort study designed to characterize the humoral and cellular immune responses induced by a subunit influenza vaccine (manufactured by Ab\&B Bio-tech Co., Ltd.JS) in healthy adults within one month after vaccination. Eligible participants will receive a single intramuscular dose and will be assigned in parallel to one of two blood-sampling schedules to capture the kinetic profile of the immune response: Group A (pre-vaccination, Day 5, and Day 14 post-vaccination) and Group B (pre-vaccination, Day 7, and Day 21 post-vaccination). Hemagglutination inhibition (HI) antibody titers will be measured to assess humoral immunity, while circulating CD4⁺ and CD8⁺ T-cell levels will be analyzed to evaluate cellular immunity. The occurrence of adverse events（AEs) and serious adverse events(SAEs) within 28 days post-vaccination will be recorded.

Read the detailed description

Study Objectives The primary objective of this study is to describe the time course of humoral and cellular immune responses within one month after a single dose of the subunit influenza vaccine in healthy adults. Secondary objectives include: (1) exploring the onset time window of vaccine-induced immunity; (2) evaluating the immunogenicity of the vaccine as measured by HI antibody seroconversion and T-cell subset dynamics; and (3) assessing the safety of the vaccine during the 28-day post-vaccination surveillance period.

Study Design

This is a prospective, open-label, parallel time-cohort study. Enrolled participants will receive one intramuscular injection of the study vaccine into the lateral aspect of the upper deltoid. Participants will be assigned in parallel to one of two sampling cohorts, each comprising three study visits:

Group A: Venous blood collected at three time points - Day 0 (pre-vaccination), Day 5, and Day 14 post-vaccination.
Group B: Venous blood collected at three time points - Day 0 (pre-vaccination), Day 7, and Day 21 post-vaccination.

At each visit, approximately 20 mL of venous blood will be drawn. Of this, 5 mL will be collected in a non-anticoagulant tube for serum separation and hemagglutination inhibition (HI) antibody testing, and 15 mL will be collected in an anticoagulant tube for peripheral blood mononuclear cell (PBMC) isolation and subsequent flow cytometric analysis of CD4⁺ and CD8⁺ T-cell populations.

Study Population Healthy adults who meet the eligibility criteria, including a complete medical history, physical examination, and screening laboratory results.

Safety Monitoring All participants will remain under direct medical observation for at least 30 minutes immediately after vaccination. The occurrence of adverse events (AEs) and serious adverse events (SAEs) within 28 days post-vaccination will be collected and recorded, including solicited local reactions (pain, swelling, erythema, induration, pruritus, ecchymosis) and systemic events (fever, cough, headache, fatigue, myalgia, arthralgia, gastrointestinal symptoms, rash, etc.).

Ethics The study has been reviewed and approved by the Ethics Review Committee of Zhejiang Provincial Center for Disease Control and Prevention. All participants will provide written informed consent prior to study enrollment. Participation is voluntary, and participants may withdraw at any time without penalty.

Conditions: Influenza
Being tested: Group A, Group B
Keywords: Influenza, Human, Immune Response, Safety, Healthy Adults, Subunit Influenza Vaccine
Medical subject headings: Influenza, Human

What participants receive

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

Group ABiological
Participants will receive one dose of Subunit Influenza Vaccine
Group BBiological
Participants will receive one dose of Subunit Influenza Vaccine

Study groups in NCT07854392
Study group	Role	What they receive
Group A	Experimental	Not described Receives: Biological: Group A
Group B	Experimental	Not described Receives: Biological: Group B

What is being measured

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

GMTs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Influenza A includes H1N1 and H3N2; influenza B includes Victoria-lineage. Geometric mean HI antibody titer for each strain will be calculated with two-sided 95% CIs.
Measured: Day 21 post-vaccination (Group B)
GMIs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Geometric mean fold increase in HI antibody titer from pre-vaccination (Day 0) to Day 21 for each strain, with two-sided 95% CIs.
Measured: Day 21 post-vaccination (Group B)
SCRs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Seroconversion is defined as either a pre-vaccination HI titer <1:10 with a post-vaccination titer ≥1:40, or a pre-vaccination HI titer ≥1:10 with at least a four-fold increase in titer.
Measured: Day 21 post-vaccination (Group B)
SPRs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Seroprotection is defined as an HI titer ≥1:40.
Measured: Day 21 post-vaccination (Group B)

Secondary outcomes (7)

GMTs of HI antibodies against the three vaccine strains (Group A, Day 5 and Day 14 post-vaccination)
Influenza A includes H1N1 and H3N2; influenza B includes Victoria-lineage. GMTs will be calculated for each strain at Day 5 and Day 14 in Group A.
Measured: Day 5 and Day 14 post-vaccination (Group A)
GMTs of HI antibodies against the three vaccine strains (Group B, Day 7 post-vaccination)
Influenza A includes H1N1 and H3N2; influenza B includes Victoria-lineage. GMTs will be calculated for each strain at Day 7 in Group B.
Measured: Day 7 post-vaccination (Group B)
Antigen-specific CD4⁺ T-cell counts and proportions (Group A: Day 0, Day 5, Day 14; Group B: Day 0, Day 7, Day 21)
Number and percentage of antigen-specific CD4⁺ T cells will be measured by flow cytometry at all three time points in Group A and Group B.
Measured: Day 0, Day 5, Day 14 (Group A); Day 0, Day 7, Day 21(Group B:)
Antigen-specific CD8⁺ T-cell counts and proportions (Group A: Day 0, Day 5, Day 14; Group B: Day 0, Day 7, Day 21)
Number and percentage of antigen-specific CD8⁺ T cells will be measured by flow cytometry at all three time points in Group A and Group B.
Measured: Day 0, Day 5, Day 14 (Group A); Day 0, Day 7, Day 21(Group B)
CD4⁺/CD8⁺ T-cell ratio (Group A: Day 0, Day 5, Day 14; Group B: Day 0, Day 7, Day 21)
The ratio of CD4⁺ to CD8⁺ T cells will be calculated at all three time points in Group A and Group B.
Measured: Day 0, Day 5, Day 14 (Group A); Day 0, Day 7, Day 21(Group B)
Occurrence of AEs (within 28 days post-vaccinatio)
Adverse events occurring within 28 days of vaccination will be recorded, including solicited local and systemic reactions.
Measured: Within 28 days post-vaccination
Occurrence of SAEs (within 28 days post-vaccination)
Serious adverse events occurring within 28 days of vaccination will be recorded.
Measured: Within 28 days post-vaccination

Timeline

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

10 Oct 202611 Oct 2027

First posted2 Oct 2026
Study start10 Oct 2026
Primary completion30 Nov 2026 (estimated)
Study completion11 Oct 2027 (estimated)

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Other trials for 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 4
Primary purpose: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: None (open label)
Enrolment: 138 participants (estimated)

IDs, dates and publications

ClinicalTrials.gov ID: NCT07854392
Sponsor's protocol ID: K-2026-070-01
Status last verified: Oct 2026
First submitted: 27 Sep 2026
Last updated: 16 Oct 2026
Results posted: No
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No

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?

See locations

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All Influenza trials

Study at a glance

From the registry record, last updated by the sponsor on 16 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A Phase IV, Prospective, Open-label, Parallel Time-cohort Study to Evaluate the Immune Responses and Safety ofSubunit Influenza Vaccine in Healthy Adults
ClinicalTrials.gov ID: NCT07854392
Acronym / sponsor ID: K-2026-070-01
Conditions: Influenza
Keywords: Influenza, Human, Immune Response, Safety, Healthy Adults, Subunit Influenza Vaccine
Phase: Phase 4
Study type: Interventional
Recruitment status: Active, not recruiting
Enrolment: 138 participants (estimated)
Lead sponsor: Ab&B Bio-tech Co., Ltd.JSUniversity, hospital or other
Collaborators: Zhejiang Provincial Center for Disease Control and Prevention, Shangyu District Center for Disease Control and Prevention
Study start: 10 Oct 2026 (actual)
Primary completion: 30 Nov 2026 (estimated)
Study completion: 11 Oct 2027 (estimated)
First posted: 2 Oct 2026 (actual)
Results: Not posted in the source record

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study Design

Group A: Venous blood collected at three time points - Day 0 (pre-vaccination), Day 5, and Day 14 post-vaccination.
Group B: Venous blood collected at three time points - Day 0 (pre-vaccination), Day 7, and Day 21 post-vaccination.

Study Population Healthy adults who meet the eligibility criteria, including a complete medical history, physical examination, and screening laboratory results.

Study design

Primary purpose: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: None (open label)
Number of arms: 2

Arm	Type	Receives
Group A	Experimental	Biological: Group A
Group B	Experimental	Biological: Group B

Who may qualify

Ages: 18 to 59 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (3 listed)

Adults aged between 18 and 59 years at the time of informed consent signature.
Judged by the investigator to be in good health, based on medical history and physical examination findings obtained at screening.
Able to comprehend and voluntarily provide written informed consent, and willing to comply with all study procedures and requirements.

Key exclusion criteria (29 listed)

Known allergy to any component of the vaccine, including excipients, formaldehyde, or Triton N-101.
Confirmed influenza infection or influenza-like illness within the past 6 months, or close contact with a confirmed influenza case within 14 days prior to the screening visit.
Receipt of any influenza vaccine (licensed or investigational) within the past 6 months.
Receipt of any licensed vaccine within 28 days prior to study vaccination, or planned receipt of any licensed vaccine within 28 days after study vaccination.
Receipt of blood products or immunoglobulin within the past 3 months, or planned receipt within 1 month after study vaccination.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Group AParticipants will receive one dose of Subunit Influenza Vaccine	Biological	Group A
Group BParticipants will receive one dose of Subunit Influenza Vaccine	Biological	Group B

Primary outcome

GMTs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Time frame: Day 21 post-vaccination (Group B)
Influenza A includes H1N1 and H3N2; influenza B includes Victoria-lineage. Geometric mean HI antibody titer for each strain will be calculated with two-sided 95% CIs.
GMIs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Time frame: Day 21 post-vaccination (Group B)
Geometric mean fold increase in HI antibody titer from pre-vaccination (Day 0) to Day 21 for each strain, with two-sided 95% CIs.
SCRs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Time frame: Day 21 post-vaccination (Group B)
Seroconversion is defined as either a pre-vaccination HI titer <1:10 with a post-vaccination titer ≥1:40, or a pre-vaccination HI titer ≥1:10 with at least a four-fold increase in titer.
SPRs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Time frame: Day 21 post-vaccination (Group B)
Seroprotection is defined as an HI titer ≥1:40.

7 secondary outcomes

GMTs of HI antibodies against the three vaccine strains (Group A, Day 5 and Day 14 post-vaccination)
Time frame: Day 5 and Day 14 post-vaccination (Group A)
GMTs of HI antibodies against the three vaccine strains (Group B, Day 7 post-vaccination)
Time frame: Day 7 post-vaccination (Group B)
Antigen-specific CD4⁺ T-cell counts and proportions (Group A: Day 0, Day 5, Day 14; Group B: Day 0, Day 7, Day 21)
Time frame: Day 0, Day 5, Day 14 (Group A); Day 0, Day 7, Day 21(Group B:)
Antigen-specific CD8⁺ T-cell counts and proportions (Group A: Day 0, Day 5, Day 14; Group B: Day 0, Day 7, Day 21)
Time frame: Day 0, Day 5, Day 14 (Group A); Day 0, Day 7, Day 21(Group B)
CD4⁺/CD8⁺ T-cell ratio (Group A: Day 0, Day 5, Day 14; Group B: Day 0, Day 7, Day 21)
Time frame: Day 0, Day 5, Day 14 (Group A); Day 0, Day 7, Day 21(Group B)
Occurrence of AEs (within 28 days post-vaccinatio)
Time frame: Within 28 days post-vaccination
Occurrence of SAEs (within 28 days post-vaccination)
Time frame: Within 28 days post-vaccination

Results and safety

This study is still under way. Results are not available in the source record yet.

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 16 Oct 2026.

Related trials for Influenza

Not yet recruitingPhase 2/3
Evaluation of the Efficacy and Safety of 102D-6 in the Treatment of Acute Uncomplicated Influenza
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RecruitingPhase 2
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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

The record lists no contact. Use the official record to reach the sponsor.

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 4 study testing Group A and Group B in people with Influenza, run by Ab&B Bio-tech Co., Ltd.JS at 1 site in China.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 3 inclusion and 29 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 16 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

GMTs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination) (time frame: Day 21 post-vaccination (Group B)). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07854392.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Oct 2026.