Bird flu vaccine study: does timing matter?
NCT ID NCT07275060
First seen Jun 26, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This study is testing whether getting two doses of the H5N1 bird flu vaccine 3 weeks apart works as well as getting them 8 weeks apart. It involves 312 healthy adults aged 18-59. The goal is to see which schedule provides better protection against the virus.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- H5N1 vaccine (Arepanrix)
- What this could lead to
- If successful, this could help determine the best timing for H5N1 vaccine doses to protect people at high risk of bird flu exposure.
- What could go wrong
- This is a small, early-phase study (312 people) comparing two schedules of an already-approved vaccine, so it may not lead to major changes. The vaccine may not work as well against new virus strains.
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 4
Runs after approval, following long-term safety and how well the treatment works in everyday use.
- Participants
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About 312 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Oct 2025
- Expected to finish
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Sep 2027
An estimate. End dates often move.
- Lead sponsor
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A research network
The lead sponsor is a research network or cooperative group.
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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18 to 59 years
- 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: 1. Individuals in stable health (defined as no new onset or exacerbation of pre-existing chronic disease three months prior to vaccination) 18-59 years of age. 2. Able to comply with the trial procedures. 3. Informed consent signed prior to trial-specific procedures. 4. If a person is at risk of becoming pregnant, has practiced adequate contraception for 28 days prior to visit 1, and has a negative pregnancy test on the day of vaccination and has agreed to continue adequate contraception until 60 days after the final vaccination. Risk of pregnancy is defined as any cis woman and/or gender divergent individual assigned female at birth or with reproductive capacity who is sexually active with individuals with sperm-producing capabilities. Individual who are post-menopausal or permanently sterile (hysterectomy, bilateral salpingectomy) are not considered at risk of pregnancy. A post-menopausal state is defined as a no menses for 12 months. Effective contraception methods are: * Combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation: * Oral * Intravaginal * Transdermal * Progestogen-only hormonal contraception associated with inhibition of ovulation: * Oral * Injectable * Implantable * Intra-uterine device (IUD) with or without hormonal release. * Vasectomised partner, provided that this partner is your sole sexual partner and that the vasectomised partner has received a medical assessment of the surgical success. * Credible self-reported history of heterosexual abstinence prior to and for at least 28 days after the vaccine. Effective contraception methods are: * Combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation: * Oral * Intravaginal * Transdermal * Progestogen-only hormonal contraception associated with inhibition of ovulation: * Oral * Injectable * Implantable * Intra-uterine device (IUD) with or without hormonal release. * Vasectomised partner, provided that this partner is your sole sexual partner and that the vasectomised partner has received a medical assessment of the surgical success. * Credible self-reported history of heterosexual abstinence prior to and for at least 28 days after the vaccine. Exclusion Criteria: * Any of the following: 1. Receipt of avian influenza A(H5N1) vaccine anytime. 2. Positive pregnancy test prior to vaccination, or breastfeeding. 3. Receipt of immunoglobulins and/or any blood products within 3 months preceding the first dose of study vaccine and for one month after the last dose of study vaccine (except Rho D). 4. Bleeding disorder or history of significant bleeding following IM injections or venipuncture. 5. Any confirmed or suspected immunosuppressive or immunodeficient state; asplenia, or immunosuppressant medication within the past 6 months except short term oral steroids (≤14 days duration) or topical steroids. 6. A significant acute disease or temperature ≥38 Co within 24 hours prior to vaccination (temporary exclusion criteria, participants can return for evaluation to be randomized/ vaccinated 72 hours after symptoms resolve). 7. Unstable chronic medical condition requiring ongoing follow-up and monitoring by a physician as determined by the investigator. 8. History of anaphylaxis or allergy to any of the constituents or trace residues of the study vaccine, including egg protein. 9. Receipt of non-study vaccine(s) 2 weeks prior to the study vaccine or planned 2 weeks after administration of the study vaccine.
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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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CHU de Québec
Québec, Quebec, G1E 7G9, Canada
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Canadian Center for Vaccinology
Halifax, Nova Scotia, Canada
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Vaccine Evaluation Center
Vancouver, British Columbia, Canada
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Vaccine Study Centre of the McGill University Health Centre
Pierrefonds, Quebec, H9H 4Y6, Canada
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