One shot for two viruses? new combo vaccine trial shows promise
NCT ID NCT06695130
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study tested a single combination vaccine that targets both COVID-19 and influenza in adults aged 50 and older. About 980 participants received either the combo shot, the flu vaccine alone, the COVID-19 vaccine alone, or separate shots in each arm. Researchers monitored safety and immune responses for one year. The goal is to see if one injection can effectively protect against both viruses.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Combination vaccine (recombinant influenza vaccine plus adjuvanted recombinant COVID-19 vaccine)
- What this could lead to
- If successful, this could lead to a single annual shot that protects against both COVID-19 and influenza, simplifying vaccination for older adults.
- What could go wrong
- This is an early-phase trial (Phase 1/2) with only 980 participants, so results may not confirm broad effectiveness or safety. The combination might not work as well as separate vaccines.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 1/2
Runs two stages together: safety and dose first, then whether the treatment works.
- Participants
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980 people
The number who actually took part.
- Started
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Nov 2024
- Finished
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Apr 2026
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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50 years and older
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: Inclusion criteria to be checked at Screening Visit: * Aged 50 years or older on the day of inclusion Informed consent * Informed consent form has been signed and dated. * Able to attend all scheduled visits and to comply with all study procedures. * Participant must be able to receive an injection in the deltoid muscle of both arms. * Participant must have completed a primary vaccination series against SARS-CoV-2 and at least 1 booster with a locally authorized or approved COVID-19 vaccine. Inclusion criteria to be checked at Visit 1 (Day \[D\]01): * Aged 50 years or older on the day of inclusions * Participants who are healthy or with pre-existing stable condition (defined as disease not requiring significant change in therapy or hospitalization for worsening disease during the 12 weeks before enrollment), as determined by medical evaluation including medical history and physical examination. * A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies: * Is of non-childbearing potential. To be considered of non-childbearing potential, a female must be post-menopausal for at least 1 year, or surgically sterile. OR • Is of childbearing potential and agrees to use an effective contraceptive method or abstinence from at least 4 weeks prior to study intervention administration until at least 4 weeks after study intervention administration. A female participant of childbearing potential must have a negative highly sensitive pregnancy test (urine or serum as required by local regulation) on the day of enrollment before the first dose of study intervention. * Informed consent form has been signed and dated. * Able to attend all scheduled visits and to comply with all study procedures. * Participant must be able to receive an injection in the deltoid muscle of both arms. * Participant must have completed a primary vaccination series against SARS-CoV-2 and at least 1 booster with a locally authorized or approved COVID-19 vaccine. Exclusion Criteria to be checked at Screening Visit and at Visit 1 (D01): * Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (for glucocorticoids, ≥ 10 milligrams/day of prednisone or equivalent for more than 2 consecutive weeks within the past 3 months). * Known systemic hypersensitivity to any of the study intervention components, or history of a life-threatening reaction to the study interventions used in the study or to a product containing any of the same substances . * Self-reported thrombocytopenia, contraindicating intramuscular injection, based on investigator's judgment. * Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular injection, based on investigator's judgment. * Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion . * Any illness that, in the opinion of the investigator, would pose a health risk to the participant if enrolled. * Moderate or severe acute illness/infection (according to investigator judgment) or febrile illness (temperature ≥ 100.4°F) on the day of study intervention administration. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided. * Alcohol, prescription drug, or substance abuse that, in the opinion of the Investigator, might interfere with the study conduct or completion. * History of serious adverse reaction to any influenza or COVID-19 vaccines. * Personal or family history of Guillain-Barré syndrome. * Prior history of myocarditis, pericarditis, or myopericarditis. * Prior history of stroke or stroke risk factors, which may include untreated/uncontrolled hypertension, hyperlipidemia, or diabetes; active smoking; obesity, based on investigator's judgment; history of thromboembolic disease; cardiac structural abnormality; atrial fibrillation; carotid stent placement; or family history of stroke. Prior/concomitant therapy * Receipt of any vaccine in the 4 weeks preceding study intervention administration or planned receipt of any vaccine prior to the second blood draw (ie, approximately in the 28 days following study intervention administration. * Previous vaccination against influenza (in the previous 6 months) with an investigational or marketed vaccine. * Previous vaccination against COVID-19 (in the previous 6 months) with an investigational or marketed vaccine OR history of COVID-19 in the previous 6 months. * Receipt of immune globulins, blood or blood-derived products in the past 3 months
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Central Phoenix Medical Clinic- Site Number : 8400009
Phoenix, Arizona, 85020, United States
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Optimal Research - Florida- Site Number : 8400006
Melbourne, Florida, 32934, United States
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Optimal Research - Illinois- Site Number : 8400008
Peoria, Illinois, 61614, United States
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Synexus Clinical Research US - Anderson- Site Number : 8400001
Anderson, South Carolina, 29621, United States
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Synexus Clinical Research US - Cincinnati- Site Number : 8400003
Cincinnati, Ohio, 45236, United States
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Synexus Clinical Research US - Evansville- Site Number : 8400004
Evansville, Indiana, 47714, United States
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Synexus Clinical Research US - Minneapolis- Site Number : 8400011
Richfield, Minnesota, 55423, United States
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Synexus Clinical Research US - Orlando- Site Number : 8400007
Orlando, Florida, 32806, United States
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Synexus Clinical Research US - Vista- Site Number : 8400010
Vista, California, 92083, United States
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Synexus Clinical Research US, Inc. - Cerritos- Site Number : 8400002
Cerritos, California, 90704, United States
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Synexus-Las Vegas- Site Number : 8400005
Las Vegas, Nevada, 89113, United States
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Walgreens Clinical Trials-Malden- Site Number : 8400012
Malden, Massachusetts, 02148, United States
More trials for these conditions
Other studies related to the condition(s) this trial covers.
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