Influenza,HumanPhase 1/2NCT06683352

A Study to Learn About Flu and COVID-19 Vaccine Responses in Healthy People

A Phase 1/2 study testing Investigational Influenza Vaccine, COVID-19 Vaccine and Investigational Influenza/COVID-19 Vaccine in people with Influenza,Human and COVID-19, run by BioNTech SE at 22 sites in United States.

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 is to learn about flu and COVID vaccines, either alone or when mixed together. Healthy people aged 18 or older can join. Participants will get one shot in each arm, either a flu or COVID vaccine, alone or mixed. Read more about this study

Who is it for?: Ages 18 years and olderHealthy volunteers can take part
Conditions the study is for: Influenza,Human, COVID-19
What is being tested?: Investigational Influenza Vaccine, COVID-19 Vaccine and Investigational Influenza/COVID-19 Vaccine
Type of treatment: Vaccines
Could I receive a placebo?: Yes, some participants may receive a placebo
How many people: 1,353 participants
Where: 22 sitesUnited States
Study dates: 11 Nov 2024to 15 Jul 2025
Phase: Phase 1/2
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 years and older
All sexes
Healthy volunteers accepted
Adult, Older adult

Who may be able to join

Participants 18 years of age or older
Healthy participants who are determined by medical history, physical examination (if clinically required), and clinical judgment of the investigator to be eligible for inclusion in the study.

Who cannot join

Vaccination with any investigational or licensed 2024-2025 season formulation influenza or COVID-19 vaccine.
Treated with antiviral therapies for influenza (eg, Tamiflu) within 180 days prior to Day 1
Please refer to the study contact for further eligibility details.

Trial locations and contacts

22 sites in 1 country.

City, postcode or hospital

22 sites in 1 country

United States22 sites

Charlottesville Medical Research
Charlottesville, Virginia, 22911
Clinical Research Professionals
Chesterfield, Missouri, 63005
Indago Research & Health Center, Inc
Hialeah, Florida, 33012
East-West Medical Research Institute
Honolulu, Hawaii, 96814
DM Clinical Research- Cyfair
Houston, Texas, 77065
Orange County Research Center
Lake Forest, California, 92630
Las Vegas Clinical Trials
Las Vegas, Nevada, 89030
SMS Clinical Research
Mesquite, Texas, 75149
Miami Dade Medical Research Institute, LLC
Miami, Florida, 33176
Palm Springs Community Health Center
Miami Lakes, Florida, 33014
Clinical Research Consulting
Milford, Connecticut, 06460
Velocity Clinical Research, Omaha
Omaha, Nebraska, 68134
Headlands Research Orlando
Orlando, Florida, 32819
ActivMed Practices & Research, LLC.
Portsmouth, New Hampshire, 03801
J. Lewis Research, Inc. / Foothill Family Clinic
Salt Lake City, Utah, 84109
J. Lewis Research, Inc. / Foothill Family Clinic South
Salt Lake City, Utah, 84121
Artemis Institute for Clinical Research
San Diego, California, 92103
Bio-Kinetic Clinical Applications, LLC dba QPS-MO
Springfield, Missouri, 65802
Bio-Kinetic Clinical Applications, LLC dba QPS-MO-Screening and Recruitment Center
Springfield, Missouri, 65807
Clinical Research Atlanta
Stockbridge, Georgia, 30281
Dynamed Clinical Research, LP d/b/a DM Clinical Research
Tomball, Texas, 77375
Diablo Clinical Research, Inc.
Walnut Creek, California, 94598

Other trials in United States

About this study

Official title: A PHASE 1/2, RANDOMIZED, OBSERVER-BLINDED STUDY TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF COMBINED VACCINE CANDIDATES AGAINST INFLUENZA AND COVID-19 IN HEALTHY INDIVIDUALS

Conditions: Influenza,Human, COVID-19
Being tested: Investigational Influenza Vaccine, COVID-19 Vaccine, Investigational Influenza/COVID-19 Vaccine, Licensed Influenza Vaccine 1, Licensed Influenza Vaccine 2
Medical subject headings: Influenza, Human, COVID-19

What participants receive

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

Investigational Influenza VaccineBiological
Investigational Influenza Vaccine
COVID-19 VaccineBiological
Pfizer-BioNTech COVID-19 Vaccine
Investigational Influenza/COVID-19 VaccineCombination product
Combined investigational influenza and Pfizer-BioNTech COVID-19 Vaccine
Licensed Influenza Vaccine 1Biological
Licensed Influenza Vaccine 1
Licensed Influenza Vaccine 2Biological
Licensed Influenza Vaccine 2
PlaceboOther
Saline

Study groups in NCT06683352
Study group	Role	What they receive
Arm A/AA	Experimental	Low Dose COVID-19 Vaccine and Placebo Receives: Biological: COVID-19 Vaccine; Other: Placebo
Arm B/BB	Experimental	Medium Dose COVID-19 Vaccine and Placebo Receives: Biological: COVID-19 Vaccine; Other: Placebo
Arm C/CC	Active comparator	High Dose COVID-19 Vaccine and Placebo Receives: Biological: COVID-19 Vaccine; Other: Placebo
Arm D/DD	Experimental	Low Dose Investigational Influenza Vaccine and Placebo Receives: Biological: Investigational Influenza Vaccine; Other: Placebo
Arm E	Active comparator	Licensed Influenza Vaccine 1 and Licensed COVID-19 Vaccine Receives: Biological: COVID-19 Vaccine; Biological: Licensed Influenza Vaccine 1
Arm EE	Active comparator	Licensed Influenza Vaccine 2 and Licensed COVID-19 Vaccine Receives: Biological: COVID-19 Vaccine; Biological: Licensed Influenza Vaccine 2
Arm F/FF	Experimental	Medium Dose Investigational Influenza Vaccine and Placebo Receives: Biological: Investigational Influenza Vaccine; Other: Placebo
Arm G/GG	Experimental	Low Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine and Placebo Receives: Combination Product: Investigational Influenza/COVID-19 Vaccine; Other: Placebo
Arm H/HH	Experimental	Medium Dose Investigational Influenza Vaccine/Low Dose COVID-19 Vaccine and Placebo Receives: Combination Product: Investigational Influenza/COVID-19 Vaccine; Other: Placebo
Arm I/II	Experimental	Low Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine and Placebo Receives: Combination Product: Investigational Influenza/COVID-19 Vaccine; Other: Placebo
Arm J/JJ	Experimental	High Dose Investigational Influenza Vaccine and Placebo Receives: Biological: Investigational Influenza Vaccine; Other: Placebo
Arm K/KK	Experimental	Medium Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine and Placebo Receives: Combination Product: Investigational Influenza/COVID-19 Vaccine; Other: Placebo
Arm L/LL	Experimental	Medium Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine and Placebo Receives: Combination Product: Investigational Influenza/COVID-19 Vaccine; Other: Placebo
Arm M/MM	Experimental	High Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine and Placebo Receives: Combination Product: Investigational Influenza/COVID-19 Vaccine; Other: Placebo
Arm N	Experimental	High Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine and Placebo Receives: Combination Product: Investigational Influenza/COVID-19 Vaccine; Other: Placebo

What is being measured

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

Cohort 1: Percentage of Participants With Any Local Reactions for up to 7 Days Following Vaccination
Local reactions included redness, swelling, and pain at the injection site, were recorded in the electronic dairy (e-diary) or case report form (CRF) after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol. Percentage of participants with at least 1 local reaction of grade 1 and above were reported in this outcome measure.
Measured: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]
Cohort 2: Percentage of Participants With Any Local Reactions for up to 7 Days Following Vaccination
Local reactions included redness, swelling, and pain at the injection site, were recorded in the e-diary or CRF after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol. Percentage of participants with at least 1 local reaction of grade 1 and above were reported in this outcome measure.
Measured: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]
Cohort 1: Percentage of Participants With Any Systemic Events for up to 7 Days Following Vaccination
Systemic Events: fever, diarrhea, vomiting, headache, fatigue/tiredness, chills, new or worsened muscle pain, and new or worsened joint pain, were recorded in the e-diary or CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol. Percentage of participants with at least 1 systemic event of grade 1 and above were reported in this outcome measure.
Measured: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]
Cohort 2: Percentage of Participants With Any Systemic Events for up to 7 Days Following Vaccination
Systemic Events: fever, diarrhea, vomiting, headache, fatigue/tiredness, chills, new or worsened muscle pain, and new or worsened joint pain, were recorded in the e-diary or CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol. Percentage of participants with at least 1 systemic event of grade 1 and above were reported in this outcome measure.
Measured: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]
Cohort 1: Percentage of Participants Reporting Adverse Events (AEs) From Vaccination Through 1 Month After Vaccination
An AE was defined as any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. AEs included both serious and all non-serious AEs. Serious AE (SAE) was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, any other pre-specified criteria in protocol of the study or other important medical event. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) were included in this outcome measure.
Measured: From Vaccination on Day 1 through 1 month after Vaccination [Vaccination on Day 1]
Cohort 2: Percentage of Participants Reporting AEs From Vaccination Through 1 Month After Vaccination
An AE was defined as any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. AEs included both serious and all non-serious AEs. SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, any other pre-specified criteria in protocol of the study or other important medical event. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) were included in this outcome measure.
Measured: From Vaccination on Day 1 through 1 month after Vaccination [Vaccination on Day 1]
Cohort 1: Percentage of Participants Reporting SAEs From Vaccination Through 6 Months After Vaccination
SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, and any other pre-specified criteria in protocol of the study or other important medical event. Only SAEs collected by non-systematic assessment (excluding local reactions and systematic events [if any]) were included in this outcome measure.
Measured: From Vaccination on Day 1 through 6 Months after Vaccination [Vaccination on Day 1]
Cohort 2: Percentage of Participants Reporting SAEs From Vaccination Through 6 Months After Vaccination
SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, and any other pre-specified criteria in protocol of the study or other important medical event. Only SAEs collected by non-systematic assessment (excluding local reactions and systematic events [if any]) were included in this outcome measure.
Measured: From Vaccination on Day 1 through 6 Months after Vaccination [Vaccination on Day 1]

Timeline

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

11 Nov 202415 Jul 2025

First posted12 Nov 2024
Study start11 Nov 2024
Primary completion15 Jul 2025
Study completion15 Jul 2025

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 Influenza,HumanStudies of the same condition, open and under way.
More trials run by BioNTech SEThe sponsor's other registered studies.
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 1/2
Primary purpose: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: Quadruple blind
Who is masked: Participant, Care provider, Investigator, Outcomes assessor
Enrolment: 1,353 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT06683352
Sponsor's protocol ID: C5261023
Other IDs: C5261023-C1; C5261023-C2
Status last verified: Aug 2026
First submitted: 8 Nov 2024
Last updated: 19 Aug 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: 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,Human trials

Study at a glance

From the registry record, last updated by the sponsor on 19 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A PHASE 1/2, RANDOMIZED, OBSERVER-BLINDED STUDY TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF COMBINED VACCINE CANDIDATES AGAINST INFLUENZA AND COVID-19 IN HEALTHY INDIVIDUALS
ClinicalTrials.gov ID: NCT06683352
Acronym / sponsor ID: C5261023
Conditions: Influenza,Human, COVID-19
Phase: Phase 1/2
Study type: Interventional
Recruitment status: Completed
Enrolment: 1,353 participants (actual)
Lead sponsor: BioNTech SEIndustry (pharma, biotech, devices)
Collaborators: Pfizer
Study start: 11 Nov 2024 (actual)
Primary completion: 15 Jul 2025 (actual)
Study completion: 15 Jul 2025 (actual)
First posted: 12 Nov 2024 (actual)
Results: Posted 19 Aug 2026

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: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: Quadruple blind (participant, care provider, investigator, outcomes assessor)
Number of arms: 15

Arm	Type	Receives
Arm A/AA	Experimental	Biological: COVID-19 Vaccine, Other: PlaceboLow Dose COVID-19 Vaccine and Placebo
Arm B/BB	Experimental	Biological: COVID-19 Vaccine, Other: PlaceboMedium Dose COVID-19 Vaccine and Placebo
Arm C/CC	Active comparator	Biological: COVID-19 Vaccine, Other: PlaceboHigh Dose COVID-19 Vaccine and Placebo
Arm D/DD	Experimental	Biological: Investigational Influenza Vaccine, Other: PlaceboLow Dose Investigational Influenza Vaccine and Placebo
Arm E	Active comparator	Biological: COVID-19 Vaccine, Biological: Licensed Influenza Vaccine 1Licensed Influenza Vaccine 1 and Licensed COVID-19 Vaccine
Arm EE	Active comparator	Biological: COVID-19 Vaccine, Biological: Licensed Influenza Vaccine 2Licensed Influenza Vaccine 2 and Licensed COVID-19 Vaccine
Arm F/FF	Experimental	Biological: Investigational Influenza Vaccine, Other: PlaceboMedium Dose Investigational Influenza Vaccine and Placebo
Arm G/GG	Experimental	Combination Product: Investigational Influenza/COVID-19 Vaccine, Other: PlaceboLow Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine and Placebo
Arm H/HH	Experimental	Combination Product: Investigational Influenza/COVID-19 Vaccine, Other: PlaceboMedium Dose Investigational Influenza Vaccine/Low Dose COVID-19 Vaccine and Placebo
Arm I/II	Experimental	Combination Product: Investigational Influenza/COVID-19 Vaccine, Other: PlaceboLow Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine and Placebo
Arm J/JJ	Experimental	Biological: Investigational Influenza Vaccine, Other: PlaceboHigh Dose Investigational Influenza Vaccine and Placebo
Arm K/KK	Experimental	Combination Product: Investigational Influenza/COVID-19 Vaccine, Other: PlaceboMedium Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine and Placebo
Arm L/LL	Experimental	Combination Product: Investigational Influenza/COVID-19 Vaccine, Other: PlaceboMedium Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine and Placebo
Arm M/MM	Experimental	Combination Product: Investigational Influenza/COVID-19 Vaccine, Other: PlaceboHigh Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine and Placebo
Arm N	Experimental	Combination Product: Investigational Influenza/COVID-19 Vaccine, Other: PlaceboHigh Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine and Placebo

Who may qualify

Ages: 18 years and older
Sex: All
Healthy volunteers: Accepted
Age groups: Adult, Older adult

Key inclusion criteria (2 listed)

Participants 18 years of age or older
Healthy participants who are determined by medical history, physical examination (if clinically required), and clinical judgment of the investigator to be eligible for inclusion in the study.

Key exclusion criteria (3 listed)

Vaccination with any investigational or licensed 2024-2025 season formulation influenza or COVID-19 vaccine.
Treated with antiviral therapies for influenza (eg, Tamiflu) within 180 days prior to Day 1
Please refer to the study contact for further eligibility details.

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
Investigational Influenza VaccineInvestigational Influenza Vaccine	Biological	Arm D/DD, Arm F/FF, Arm J/JJ
COVID-19 VaccinePfizer-BioNTech COVID-19 Vaccine	Biological	Arm A/AA, Arm B/BB, Arm C/CC, Arm E, Arm EE
Investigational Influenza/COVID-19 VaccineCombined investigational influenza and Pfizer-BioNTech COVID-19 Vaccine	Combination product	Arm G/GG, Arm H/HH, Arm I/II, Arm K/KK, Arm L/LL, Arm M/MM, Arm N
Licensed Influenza Vaccine 1Licensed Influenza Vaccine 1	Biological	Arm E
Licensed Influenza Vaccine 2Licensed Influenza Vaccine 2	Biological	Arm EE
PlaceboSaline	Other	Arm A/AA, Arm B/BB, Arm C/CC, Arm D/DD, Arm F/FF, Arm G/GG, Arm H/HH, Arm I/II, Arm J/JJ, Arm K/KK, Arm L/LL, Arm M/MM, Arm N

Primary outcome

Cohort 1: Percentage of Participants With Any Local Reactions for up to 7 Days Following Vaccination
Time frame: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]
Local reactions included redness, swelling, and pain at the injection site, were recorded in the electronic dairy (e-diary) or case report form (CRF) after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol. Percentage of participants with at least 1 local reaction of grade 1 and above were reported in this outcome measure.
Cohort 2: Percentage of Participants With Any Local Reactions for up to 7 Days Following Vaccination
Time frame: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]
Local reactions included redness, swelling, and pain at the injection site, were recorded in the e-diary or CRF after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol. Percentage of participants with at least 1 local reaction of grade 1 and above were reported in this outcome measure.
Cohort 1: Percentage of Participants With Any Systemic Events for up to 7 Days Following Vaccination
Time frame: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]
Systemic Events: fever, diarrhea, vomiting, headache, fatigue/tiredness, chills, new or worsened muscle pain, and new or worsened joint pain, were recorded in the e-diary or CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol. Percentage of participants with at least 1 systemic event of grade 1 and above were reported in this outcome measure.
Cohort 2: Percentage of Participants With Any Systemic Events for up to 7 Days Following Vaccination
Time frame: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]
Systemic Events: fever, diarrhea, vomiting, headache, fatigue/tiredness, chills, new or worsened muscle pain, and new or worsened joint pain, were recorded in the e-diary or CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol. Percentage of participants with at least 1 systemic event of grade 1 and above were reported in this outcome measure.
Cohort 1: Percentage of Participants Reporting Adverse Events (AEs) From Vaccination Through 1 Month After Vaccination
Time frame: From Vaccination on Day 1 through 1 month after Vaccination [Vaccination on Day 1]
An AE was defined as any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. AEs included both serious and all non-serious AEs. Serious AE (SAE) was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, any other pre-specified criteria in protocol of the study or other important medical event. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) were included in this outcome measure.
Cohort 2: Percentage of Participants Reporting AEs From Vaccination Through 1 Month After Vaccination
Time frame: From Vaccination on Day 1 through 1 month after Vaccination [Vaccination on Day 1]
An AE was defined as any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. AEs included both serious and all non-serious AEs. SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, any other pre-specified criteria in protocol of the study or other important medical event. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) were included in this outcome measure.
Cohort 1: Percentage of Participants Reporting SAEs From Vaccination Through 6 Months After Vaccination
Time frame: From Vaccination on Day 1 through 6 Months after Vaccination [Vaccination on Day 1]
SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, and any other pre-specified criteria in protocol of the study or other important medical event. Only SAEs collected by non-systematic assessment (excluding local reactions and systematic events [if any]) were included in this outcome measure.
Cohort 2: Percentage of Participants Reporting SAEs From Vaccination Through 6 Months After Vaccination
Time frame: From Vaccination on Day 1 through 6 Months after Vaccination [Vaccination on Day 1]
SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, and any other pre-specified criteria in protocol of the study or other important medical event. Only SAEs collected by non-systematic assessment (excluding local reactions and systematic events [if any]) were included in this outcome measure.

Results and safety

Results posted to the registry on 19 Aug 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Cohort 1, Arm A: Low Dose COVID-19 Vaccine + Placebo	51	49
Cohort 1, Arm B: Medium Dose COVID-19 Vaccine + Placebo	50	49
Cohort 1, Arm C: High Dose COVID-19 Vaccine + Placebo	50	49
Cohort 1, Arm D: Low Dose Investigational Influenza Vaccine + Placebo	50	47
Cohort 1, Arm E: Licensed Influenza Vaccine 1 + Licensed COVID-19 Vaccine	50	48
Cohort 1, Arm F: Medium Dose Investigational Influenza Vaccine + Placebo	50	48
Cohort 1, Arm G: Low Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo	50	47
Cohort 1, Arm H: Medium Dose Investigational Influenza Vaccine/Low Dose COVID-19 Vaccine + Placebo	50	48
Cohort 1, Arm I: Low Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo	50	48
Cohort 1, Arm J: High Dose Investigational Influenza Vaccine + Placebo	50	43
Cohort 1, Arm K: Medium Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine +Placebo	51	50
Cohort 1, Arm L: Medium Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo	50	48
Cohort 1, Arm M: High Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo	50	50
Cohort 1, Arm N: High Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo	50	45
Cohort 2, Arm AA: Low Dose COVID-19 Vaccine + Placebo	50	48
Cohort 2, Arm BB: Medium Dose COVID-19 Vaccine + Placebo	50	50
Cohort 2, Arm CC: High Dose COVID-19 Vaccine + Placebo	50	48
Cohort 2, Arm DD: Low Dose Investigational Influenza Vaccine + Placebo	51	46
Cohort 2, Arm EE: Licensed Influenza Vaccine 2 + Licensed COVID-19 Vaccine	50	48
Cohort 2, Arm FF: Medium Dose Investigational Influenza Vaccine + Placebo	50	49
Cohort 2, Arm GG: Low Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo	50	49
Cohort 2, Arm HH: Medium Dose Investigational Influenza Vaccine/Low Dose COVID-19 Vaccine + Placebo	50	49
Cohort 2, Arm II: Low Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo	50	47
Cohort 2, Arm JJ: High Dose Investigational Influenza Vaccine + Placebo	50	48
Cohort 2, Arm KK: Medium Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine+Placebo	50	48
Cohort 2, Arm LL: Medium Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo	50	49
Cohort 2, Arm MM: High Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo	50	48

Primary outcome: Cohort 1: Percentage of Participants With Any Local Reactions for up to 7 Days Following Vaccination

Time frame: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	Cohort 1, Arm A: Low Dose COVID-19 Vaccine + Placebo n = 50	Cohort 1, Arm B: Medium Dose COVID-19 Vaccine + Placebo n = 49	Cohort 1, Arm C: High Dose COVID-19 Vaccine + Placebo n = 49	Cohort 1, Arm D: Low Dose Investigational Influenza Vaccine + Placebo n = 50	Cohort 1, Arm E: Licensed Influenza Vaccine 1 + Licensed COVID-19 Vaccine n = 50	Cohort 1, Arm F: Medium Dose Investigational Influenza Vaccine + Placebo n = 50	Cohort 1, Arm G: Low Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo n = 50	Cohort 1, Arm H: Medium Dose Investigational Influenza Vaccine/Low Dose COVID-19 Vaccine + Placebo n = 50	Cohort 1, Arm I: Low Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo n = 49	Cohort 1, Arm J: High Dose Investigational Influenza Vaccine + Placebo n = 48	Cohort 1, Arm K: Medium Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine +Placebo n = 51	Cohort 1, Arm L: Medium Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo n = 50	Cohort 1, Arm M: High Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo n = 49	Cohort 1, Arm N: High Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo n = 50
Value	50.0 (35.5 to 64.5)	61.2 (46.2 to 74.8)	65.3 (50.4 to 78.3)	80.0 (66.3 to 90.0)	42.0 (28.2 to 56.8)	70.0 (55.4 to 82.1)	74.0 (59.7 to 85.4)	72.0 (57.5 to 83.8)	79.6 (65.7 to 89.8)	89.6 (77.3 to 96.5)	78.4 (64.7 to 88.7)	86.0 (73.3 to 94.2)	69.4 (54.6 to 81.7)

Primary outcome: Cohort 2: Percentage of Participants With Any Local Reactions for up to 7 Days Following Vaccination

Time frame: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	Cohort 2, Arm AA: Low Dose COVID-19 Vaccine + Placebo n = 50	Cohort 2, Arm BB: Medium Dose COVID-19 Vaccine + Placebo n = 50	Cohort 2, Arm CC: High Dose COVID-19 Vaccine + Placebo n = 49	Cohort 2, Arm DD: Low Dose Investigational Influenza Vaccine + Placebo n = 50	Cohort 2, Arm EE: Licensed Influenza Vaccine 2 + Licensed COVID-19 Vaccine n = 49	Cohort 2, Arm FF: Medium Dose Investigational Influenza Vaccine + Placebo n = 50	Cohort 2, Arm GG: Low Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo n = 50	Cohort 2, Arm HH: Medium Dose Investigational Influenza Vaccine/Low Dose COVID-19 Vaccine + Placebo n = 49	Cohort 2, Arm II: Low Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo n = 48	Cohort 2, Arm JJ: High Dose Investigational Influenza Vaccine + Placebo n = 50	Cohort 2, Arm KK: Medium Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine+Placebo n = 50	Cohort 2, Arm LL: Medium Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo n = 50	Cohort 2, Arm MM: High Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo n = 49
Value	30.0 (17.9 to 44.6)	42.0 (28.2 to 56.8)	42.9 (28.8 to 57.8)	64.0 (49.2 to 77.1)	36.7 (23.4 to 51.7)	58.0 (43.2 to 71.8)	66.0 (51.2 to 78.8)	63.3 (48.3 to 76.6)	66.7 (51.6 to 79.6)	60.0 (45.2 to 73.6)	68.0 (53.3 to 80.5)	60.0 (45.2 to 73.6)	67.3 (52.5 to 80.1)

Population analysed: Safety analysis population included all participants who received any study intervention. Here "Overall Number of Participants Analyzed" signifies number of participants reporting at least 1 response in the e-diary or CRF after vaccination.

Primary outcome: Cohort 1: Percentage of Participants With Any Systemic Events for up to 7 Days Following Vaccination

Time frame: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	Cohort 1, Arm A: Low Dose COVID-19 Vaccine + Placebo n = 50	Cohort 1, Arm B: Medium Dose COVID-19 Vaccine + Placebo n = 49	Cohort 1, Arm C: High Dose COVID-19 Vaccine + Placebo n = 49	Cohort 1, Arm D: Low Dose Investigational Influenza Vaccine + Placebo n = 50	Cohort 1, Arm E: Licensed Influenza Vaccine 1 + Licensed COVID-19 Vaccine n = 50	Cohort 1, Arm F: Medium Dose Investigational Influenza Vaccine + Placebo n = 50	Cohort 1, Arm G: Low Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo n = 50	Cohort 1, Arm H: Medium Dose Investigational Influenza Vaccine/Low Dose COVID-19 Vaccine + Placebo n = 50	Cohort 1, Arm I: Low Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo n = 49	Cohort 1, Arm J: High Dose Investigational Influenza Vaccine + Placebo n = 48	Cohort 1, Arm K: Medium Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine +Placebo n = 51	Cohort 1, Arm L: Medium Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo n = 50	Cohort 1, Arm M: High Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo n = 49	Cohort 1, Arm N: High Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo n = 50
Value	64.0 (49.2 to 77.1)	57.1 (42.2 to 71.2)	49.0 (34.4 to 63.7)	72.0 (57.5 to 83.8)	44.0 (30.0 to 58.7)	68.0 (53.3 to 80.5)	68.0 (53.3 to 80.5)	68.0 (53.3 to 80.5)	77.6 (63.4 to 88.2)	70.8 (55.9 to 83.0)	70.6 (56.2 to 82.5)	78.0 (64.0 to 88.5)	73.5 (58.9 to 85.1)

Primary outcome: Cohort 2: Percentage of Participants With Any Systemic Events for up to 7 Days Following Vaccination

Time frame: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	Cohort 2, Arm AA: Low Dose COVID-19 Vaccine + Placebo n = 50	Cohort 2, Arm BB: Medium Dose COVID-19 Vaccine + Placebo n = 50	Cohort 2, Arm CC: High Dose COVID-19 Vaccine + Placebo n = 49	Cohort 2, Arm DD: Low Dose Investigational Influenza Vaccine + Placebo n = 50	Cohort 2, Arm EE: Licensed Influenza Vaccine 2 + Licensed COVID-19 Vaccine n = 49	Cohort 2, Arm FF: Medium Dose Investigational Influenza Vaccine + Placebo n = 50	Cohort 2, Arm GG: Low Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo n = 50	Cohort 2, Arm HH: Medium Dose Investigational Influenza Vaccine/Low Dose COVID-19 Vaccine + Placebo n = 49	Cohort 2, Arm II: Low Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo n = 48	Cohort 2, Arm JJ: High Dose Investigational Influenza Vaccine + Placebo n = 50	Cohort 2, Arm KK: Medium Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine+Placebo n = 50	Cohort 2, Arm LL: Medium Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo n = 50	Cohort 2, Arm MM: High Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo n = 49
Value	34.0 (21.2 to 48.8)	38.0 (24.7 to 52.8)	40.8 (27.0 to 55.8)	62.0 (47.2 to 75.3)	40.8 (27.0 to 55.8)	36.0 (22.9 to 50.8)	62.0 (47.2 to 75.3)	49.0 (34.4 to 63.7)	56.3 (41.2 to 70.5)	46.0 (31.8 to 60.7)	56.0 (41.3 to 70.0)	46.0 (31.8 to 60.7)	57.1 (42.2 to 71.2)

Adverse events

Time frame: Systematic assessment: Local reactions and systemic events were assessed from Vaccination on Day 1 to Day 7 after Vaccination; Non-systematic assessment: SAEs were assessed from Vaccination on Day 1 up to 6 months after Vaccination; other AEs were assessed from Vaccination on Day 1 up to 1 month after Vaccination; all-cause mortality: from Vaccination on Day 1 up to 6 months after Vaccination. Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Cohort 1, Arm A: Low Dose COVID-19 Vaccine + Placebo	0 of 51 (0%)	34 of 51 (66.7%)	0 of 51
Cohort 1, Arm B: Medium Dose COVID-19 Vaccine + Placebo	1 of 50 (2%)	35 of 50 (70%)	0 of 50
Cohort 1, Arm C: High Dose COVID-19 Vaccine + Placebo	0 of 49 (0%)	33 of 49 (67.3%)	0 of 49
Cohort 1, Arm D: Low Dose Investigational Influenza Vaccine + Placebo	1 of 50 (2%)	43 of 50 (86%)	0 of 50
Cohort 1, Arm E: Licensed Influenza Vaccine 1 + Licensed COVID-19 Vaccine	0 of 50 (0%)	26 of 50 (52%)	0 of 50
Cohort 1, Arm F: Medium Dose Investigational Influenza Vaccine + Placebo	0 of 50 (0%)	39 of 50 (78%)	0 of 50
Cohort 1, Arm G: Low Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine + Placebo	0 of 50 (0%)	41 of 50 (82%)	0 of 50
Cohort 1, Arm H: Medium Dose Investigational Influenza Vaccine/Low Dose COVID-19 Vaccine + Placebo	0 of 50 (0%)	40 of 50 (80%)	0 of 50
Cohort 1, Arm I: Low Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo	1 of 49 (2%)	42 of 49 (85.7%)	0 of 49
Cohort 1, Arm J: High Dose Investigational Influenza Vaccine + Placebo	0 of 49 (0%)	45 of 49 (91.8%)	0 of 49
Cohort 1, Arm K: Medium Dose Investigational Influenza Vaccine/Medium Dose COVID-19 Vaccine +Placebo	0 of 51 (0%)	40 of 51 (78.4%)	0 of 51
Cohort 1, Arm L: Medium Dose Investigational Influenza Vaccine/High Dose COVID-19 Vaccine + Placebo	0 of 50 (0%)	45 of 50 (90%)	0 of 50

Limitations and caveats (from the sponsor): Dose strengths for vaccines have not been disclosed in the record, as per Sponsor's decision to maintain company confidentiality; the dose strengths have been denoted as low dose, medium dose and high dose.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 19 Aug 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
To obtain contact information for a study center near you, click here.Link provided by the sponsor.
Individual participant dataSharing planned: No

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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.

Pfizer CT.gov Call Center study director

Pfizer

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

Questions about this trial

What is this clinical trial studying?

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 2 inclusion and 3 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 19 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 22 sites in United States. 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 combined phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

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 19 Aug 2026). 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?

Cohort 1: Percentage of Participants With Any Local Reactions for up to 7 Days Following Vaccination (time frame: From Day 1 through Day 7 after Vaccination [Vaccination on Day 1]). The study lists 8 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 NCT06683352.

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 19 Aug 2026.