Super-Sized flu shot aims to better shield seniors
NCT ID NCT04498832
First seen Jun 25, 2026 · Last updated Jun 26, 2026 · Updated 1 time
Summary
This study tested a high-dose flu vaccine against a standard-dose one in 2,100 adults aged 60 and older in Japan. The goal was to see if the high-dose version triggers a stronger immune response. Participants received one shot and were followed for 28 days to measure antibody levels and safety.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- High-dose quadrivalent influenza vaccine (QIV-HD)
- What this could lead to
- If successful, this could provide better protection against flu for older adults, who are at higher risk of severe illness.
- What could go wrong
- This trial is complete, but results may not apply to other populations or flu seasons. A stronger immune response doesn't always mean fewer infections.
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 3
Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.
- Participants
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2,100 people
The number who actually took part.
- Started
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Oct 2020
- Finished
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Jan 2021
- 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
-
60 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 : * Aged greater than or equal to (\>=) 60 years on the day of inclusion. * Able to attend all scheduled visits and complied with all study procedures. Exclusion criteria: * Participation at the time of study enrollment (or in the 4 weeks preceding the study vaccination) or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure. * Receipt of any vaccination with live vaccines within the past 27 days preceding the study vaccination or any vaccination with inactivated vaccines within the past 6 days preceding the study vaccination, or planned receipt of any vaccine prior to Visit 02. * Previous vaccination against influenza (in the preceding 6 months) with either the study vaccine or another vaccine. * Receipt of immune globulins, blood or blood-derived products in the past 3 months. * 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 (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months). * Known systemic hypersensitivity to eggs, chicken proteins, or any of the vaccine components, or history of a life-threatening reaction to the vaccine used in the study or to a vaccine containing any of the same substances. * Thrombocytopenia or bleeding disorder, contraindicating IM vaccination based on Investigator's judgment. * Alcohol or substance abuse that, in the opinion of the Investigator might interfere with the study conduct or completion. * Chronic illness that, in the opinion of the Investigator, was at a stage where it might interfere with study conduct or completion. * Identified as an Investigator or employee of the Investigator or study center with direct involvement in the proposed study, or identified as an immediate family member (i.e.,parent, spouse, natural or adopted child) of the Investigator or employee with direct involvement in the proposed study. * Personal or family history of Guillain-Barré syndrome. * Neoplastic disease or any hematologic malignancy (except localized skin or prostate cancer that is stable at the time of vaccination in the absence of therapy and participants who have a history of neoplastic disease and have been disease free for \>=5 years). * Moderate or severe acute illness/infection (according to Investigator judgment) on the day of vaccination or febrile illness (temperature \>=37.5 degree Celsius). A prospective participant was not be included in the study until the condition had resolved or the febrile event had subsided. * History of convulsions. * Any condition that in the opinion of the Investigator could interfere with the evaluation of the vaccine. The above information was not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.
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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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Investigational Site Number 3920001
Osaka, Japan
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Investigational Site Number 3920002
Suita-Shi, Japan
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Investigational Site Number 3920003
Shinjuku-Ku, Japan
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Investigational Site Number 3920004
Koganeishi, Japan
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Investigational Site Number 3920005
Fukuoka, Japan
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Investigational Site Number 3920006
Kumamoto, Japan
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Investigational Site Number 3920007
Toshima-Ku, Japan
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Investigational Site Number 3920008
Shinjuku-Ku, Japan
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Investigational Site Number 3920009
Shinjuku-Ku, Japan
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Investigational Site Number 3920010
Yokohama, Japan
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