COVID - 19Early Phase 1NCT06831786

Immunogenicity of COVID-19 Vaccine Co-administration With Influenza Vaccine in Healthy Volunteers

A Early Phase 1 study testing Bivalent mRNA SARS-CoV-2 vaccine and Quardrivalent influenza vaccine in people with COVID - 19, run by Prince of Songkla University at 1 site in Thailand.

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

This study, a pilot randomized controlled trial, single-blind (outcome assessor), evaluating the immune response (both humoral and cell-mediated) against SARS-CoV-2 and the safety of three different vaccine administration approaches: the SARS-CoV-2 mRNA vaccine alone, the influenza vaccine alone, and the… Read more about this study

Who is it for?: Ages 18 to 60 yearsHealthy volunteers can take part
Conditions the study is for: COVID - 19
What is being tested?: Bivalent mRNA SARS-CoV-2 vaccine and Quardrivalent influenza vaccine
Type of treatment: Vaccines
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 36 participants
Where: 1 siteThailand
Study dates: 1 Mar 2024to 31 May 2024
Phase: Early Phase 1
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 60 years
All sexes
Healthy volunteers accepted
Adult

Who may be able to join

Thai adults aged 18-60 years, who have vaccinated COVID-19 and influenza vaccine more than 6 months.
The subjects are able to and willing to comply with the requirements of the clinical trial program and could complete the 1-month follow-up of the study.
Individuals who are in good health condition at the time of entry into the trial as determined by medical history, physical examination and clinical judgment of the investigator and meet the requirements of immunization.
The subject can provide with informed consent and sign informed consent form (ICF).

Who cannot join

Have history of influenza or COVID-19 infection within 6 months.
Have the medical history or family history of convulsion, epilepsy, encephalopathy, and psychosis.
Be allergic to any component of the research vaccines or used to have a history of hypersensitivity or serious reactions to vaccination.
History of Guillain-Barré syndrome.
Women with positive urine pregnancy test, pregnant or breast-feeding, or have a pregnancy plan within six months of after baseline period.
Have infectious diseases, including HIV and SARS-CoV-2 infection or any symptom of common cold.

Show all 15Show fewer

Have history of SARS-CoV-2 infection less than 6 months.
Having severe chronic diseases or condition in progress cannot be controlled. For example, poor controlled DM and uncontrolled HT.
Have the history of urticaria 1 year before receiving the investigational vaccine.
Have known underlying diseases of thrombocytopenia or other coagulation disorders (which may cause contraindications for intramuscular injection).
Having needle sickness.
Have the history of immunosuppressive therapy, cytotoxic therapy, or systemic corticosteroids.
Have received blood products within 4 months before injection of investigational vaccines.
Under anti-tuberculosis treatment.
Not be able to follow the protocol, or not be able to understand the informed consent according to the researcher's judgment, due to various medical, psychological, social, or other conditions.

Trial locations and contacts

1 site in 1 country.

Thailand1 site

Faculty of Medicine, Prince of Songkla University
Songkhla, 90110

Other trials in Thailand

About this study

Official title: Immunogenicity to SARS-CoV-2 of Co-administering Bivalent mRNA BNT162b2 Booster and Quadrivalent Influenza Vaccine Among Healthy Volunteers: A Pilot Study

Conditions: COVID - 19
Being tested: Bivalent mRNA SARS-CoV-2 vaccine, Quardrivalent influenza vaccine
Keywords: co-administration, immunogenicity, cell-medicated immune response, influenza vaccine, COVID-19 vaccine, SARS-CoV-2 vaccine
Medical subject headings: COVID-19, Influenza, Human

What participants receive

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

Bivalent mRNA SARS-CoV-2 vaccineBiological
Administering a booster dose of the bivalent mRNA vaccine BNT162b2
Quardrivalent influenza vaccineBiological
Administering a VaxigripTetra™

Study groups in NCT06831786
Study group	Role	What they receive
Bivalent mRNA BNT162b2	Active comparator	Administering a booster dose of the bivalent mRNA vaccine BNT162b2. Receives: Biological: Bivalent mRNA SARS-CoV-2 vaccine
Quardrivalent influenza vaccine	Experimental	Administering a VaxigripTetra™ Receives: Biological: Quardrivalent influenza vaccine
Co-administration	Experimental	Co-administering bivalent mRNA vaccine BNT162b2 and VaxigripTetra™ Receives: Biological: Bivalent mRNA SARS-CoV-2 vaccine; Biological: Quardrivalent influenza vaccine

What is being measured

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

Geometric Mean (GM) of Interferon-gamma (IFN-γ) Response Against the SARS-CoV-2 Virus at Baseline
IFN-γ response against the SARS-CoV-2 virus, measured by the ELISpot assay
Measured: Before vaccination
Geometric Mean (GM) of Interferon-gamma (IFN-γ) Response Against the SARS-CoV-2 Virus at 4 Weeks
IFN-γ response against the SARS-CoV-2 virus, measured by the ELISpot assay
Measured: 4 weeks post vaccination
Geometric Mean (GM) of IgG Response Against the SARS-CoV-2 Virus at Baseline
IgG response against the SARS-CoV-2 virus, measured by ELISA.
Measured: before vaccination
Geometric Mean (GM) of IgG Response Against the SARS-CoV-2 Virus at 4 Weeks
IgG response against the SARS-CoV-2 virus, measured by ELISA.
Measured: 4 weeks post vaccination

Timeline

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

1 Mar 202431 May 2024

First posted18 Feb 2025
Study start1 Mar 2024
Primary completion31 May 2024
Study completion31 May 2024

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for COVID - 19Studies 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: Early Phase 1
Primary purpose: Basic science
Allocation: Randomised
Intervention model: Parallel groups
Masking: Single blind
Who is masked: Outcomes assessor
Enrolment: 36 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT06831786
Sponsor's protocol ID: REC.66-462-14-1
Status last verified: Nov 2025
First submitted: 15 Feb 2025
Last updated: 4 Dec 2025
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: No: The data will be kept anonymized.

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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Study at a glance

From the registry record, last updated by the sponsor on 4 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Immunogenicity to SARS-CoV-2 of Co-administering Bivalent mRNA BNT162b2 Booster and Quadrivalent Influenza Vaccine Among Healthy Volunteers: A Pilot Study
ClinicalTrials.gov ID: NCT06831786
Acronym / sponsor ID: REC.66-462-14-1
Conditions: COVID - 19
Keywords: co-administration, immunogenicity, cell-medicated immune response, influenza vaccine, COVID-19 vaccine, SARS-CoV-2 vaccine
Phase: Early Phase 1
Study type: Interventional
Recruitment status: Completed
Enrolment: 36 participants (actual)
Lead sponsor: Prince of Songkla UniversityUniversity, hospital or other
Study start: 1 Mar 2024 (actual)
Primary completion: 31 May 2024 (actual)
Study completion: 31 May 2024 (actual)
First posted: 18 Feb 2025 (actual)
Results: Posted 4 Dec 2025

Clinical summary

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

Study design

Primary purpose: Basic science
Allocation: Randomised
Intervention model: Parallel groups
Masking: Single blind (outcomes assessor)
Number of arms: 3

Arm	Type	Receives
Bivalent mRNA BNT162b2	Active comparator	Biological: Bivalent mRNA SARS-CoV-2 vaccineAdministering a booster dose of the bivalent mRNA vaccine BNT162b2.
Quardrivalent influenza vaccine	Experimental	Biological: Quardrivalent influenza vaccineAdministering a VaxigripTetra™
Co-administration	Experimental	Biological: Bivalent mRNA SARS-CoV-2 vaccine, Biological: Quardrivalent influenza vaccineCo-administering bivalent mRNA vaccine BNT162b2 and VaxigripTetra™

Who may qualify

Ages: 18 to 60 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (4 listed)

Thai adults aged 18-60 years, who have vaccinated COVID-19 and influenza vaccine more than 6 months.
The subjects are able to and willing to comply with the requirements of the clinical trial program and could complete the 1-month follow-up of the study.
Individuals who are in good health condition at the time of entry into the trial as determined by medical history, physical examination and clinical judgment of the investigator and meet the requirements of immunization.
The subject can provide with informed consent and sign informed consent form (ICF).

Key exclusion criteria (15 listed)

Have history of influenza or COVID-19 infection within 6 months.
Have the medical history or family history of convulsion, epilepsy, encephalopathy, and psychosis.
Be allergic to any component of the research vaccines or used to have a history of hypersensitivity or serious reactions to vaccination.
History of Guillain-Barré syndrome.
Women with positive urine pregnancy test, pregnant or breast-feeding, or have a pregnancy plan within six months of after baseline period.

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
Bivalent mRNA SARS-CoV-2 vaccineAdministering a booster dose of the bivalent mRNA vaccine BNT162b2	Biological	Bivalent mRNA BNT162b2, Co-administration
Quardrivalent influenza vaccineAdministering a VaxigripTetra™	Biological	Co-administration, Quardrivalent influenza vaccine

Primary outcome

Geometric Mean (GM) of Interferon-gamma (IFN-γ) Response Against the SARS-CoV-2 Virus at Baseline
Time frame: Before vaccination
IFN-γ response against the SARS-CoV-2 virus, measured by the ELISpot assay
Geometric Mean (GM) of Interferon-gamma (IFN-γ) Response Against the SARS-CoV-2 Virus at 4 Weeks
Time frame: 4 weeks post vaccination
IFN-γ response against the SARS-CoV-2 virus, measured by the ELISpot assay
Geometric Mean (GM) of IgG Response Against the SARS-CoV-2 Virus at Baseline
Time frame: before vaccination
IgG response against the SARS-CoV-2 virus, measured by ELISA.
Geometric Mean (GM) of IgG Response Against the SARS-CoV-2 Virus at 4 Weeks
Time frame: 4 weeks post vaccination
IgG response against the SARS-CoV-2 virus, measured by ELISA.

Results and safety

Results posted to the registry on 4 Dec 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
COVID-19 vaccine	12	12
Influenza vaccine	12	12
Co-administration	12	12

Primary outcome: Geometric Mean (GM) of Interferon-gamma (IFN-γ) Response Against the SARS-CoV-2 Virus at Baseline

Time frame: Before vaccination. Geometric mean (95% Confidence Interval). Unit: SFCs/10⁶ PBMCs

Measure	COVID-19 vaccine n = 12	Influenza vaccine n = 12	Co-administration n = 12
Value	19.6 (8.8 to 43.9)	14 (4.6 to 42.7)	12.6 (6.5 to 24.7)

Primary outcome: Geometric Mean (GM) of Interferon-gamma (IFN-γ) Response Against the SARS-CoV-2 Virus at 4 Weeks

Time frame: 4 weeks post vaccination. Geometric mean (95% Confidence Interval). Unit: SFCs/10⁶ PBMCs

Measure	COVID-19 vaccine n = 12	Influenza vaccine n = 12	Co-administration n = 12
Value	59.9 (26.2 to 136.9)	15.2 (4.5 to 51)	61.6 (37.1 to 102.2)

Primary outcome: Geometric Mean (GM) of IgG Response Against the SARS-CoV-2 Virus at Baseline

Time frame: before vaccination. Geometric mean (95% Confidence Interval). Unit: BAU/mL

Measure	COVID-19 vaccine n = 12	Influenza vaccine n = 12	Co-administration n = 12
Value	1276.3 (933.9 to 1744.1)	1074.2 (574.3 to 2009.3)	1299.7 (729.7 to 2314.8)

Primary outcome: Geometric Mean (GM) of IgG Response Against the SARS-CoV-2 Virus at 4 Weeks

Time frame: 4 weeks post vaccination. Geometric mean (95% Confidence Interval). Unit: BAU/mL

Measure	COVID-19 vaccine n = 12	Influenza vaccine n = 12	Co-administration n = 12
Value	10456.1 (7688.6 to 14219.7)	1008.0 (568.9 to 1786.2)	8558.7 (5666.6 to 12926.9)

Adverse events

Time frame: From vaccination until 28 days post vaccination. Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
COVID-19 vaccine	0 of 12 (0%)	12 of 12 (100%)	0 of 12
Influenza vaccine	0 of 12 (0%)	10 of 12 (83.3%)	0 of 12
Co-administration	0 of 12 (0%)	12 of 12 (100%)	0 of 12

Limitations and caveats (from the sponsor): As a single-center pilot study with a limited number of participants, the findings may not be generalizable. The short follow-up duration also restricts conclusions about long-term safety and immune responses.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 4 Dec 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Individual participant dataSharing planned: No. The data will be kept anonymized.

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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.

Sarunyou Chusri, M.D., Ph.D. principal investigator

Prince of Songkla University

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

Questions about this trial

What is this clinical trial studying?

A Early Phase 1 study testing Bivalent mRNA SARS-CoV-2 vaccine and Quardrivalent influenza vaccine in people with COVID - 19, run by Prince of Songkla University at 1 site in Thailand.

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 4 inclusion and 15 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: finished, as of the sponsor's last update on 4 Dec 2025. 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 Thailand. 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?

Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.

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

Are results available for this study?

Yes. Results are posted in the registry (first posted 4 Dec 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Geometric Mean (GM) of Interferon-gamma (IFN-γ) Response Against the SARS-CoV-2 Virus at Baseline (time frame: Before vaccination). 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 NCT06831786.

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 4 Dec 2025.