Immunogenicity and Safety of 2 Doses of Avian Influenza A (H5N1) Vaccine Administered 3 vs. 8 Wee… (NCT07275060) | Clinical Trial Compass
Active — Not RecruitingPhase 4
Immunogenicity and Safety of 2 Doses of Avian Influenza A (H5N1) Vaccine Administered 3 vs. 8 Weeks Apart
Canada312 participantsStarted 2025-10-14
Plain-language summary
Given the recent circulation of avian influenza A(H5N1) clade 2.3.4.4b strains in birds and mammals in North America, Canada procured a supply of Arepanrix™ H5N1 for potential use in persons at high risk of highly pathogenic avian influenza exposure.
This vaccine received regulatory approval in 2013, to be given in two doses at least 3 weeks apart. There is limited data on the effect of various intervals between the two doses on immunogenicity and tolerability. In this study two intervals between doses will be compared (3 vs. 8 weeks apart).
Who can participate
Age range
18 Years – 59 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. 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.
. Able to comply with the trial procedures.
. Informed consent signed prior to trial-specific procedures.
. 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.
Exclusion criteria
. Receipt of avian influenza A(H5N1) vaccine anytime.
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Percentages of participants with seroprotection against the H5N1 2.3.4.4b clade vaccine given 3 vs. 8 weeks apart
Timeframe: 28 days post-administration of 2 doses of avian influenza A (H5N1 (Approximately week 12).
. Positive pregnancy test prior to vaccination, or breastfeeding.
. 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).
. Bleeding disorder or history of significant bleeding following IM injections or venipuncture.
. 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.
. 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).
. Unstable chronic medical condition requiring ongoing follow-up and monitoring by a physician as determined by the investigator.
. History of anaphylaxis or allergy to any of the constituents or trace residues of the study vaccine, including egg protein.