Active not recruitingPHASE4INTERVENTIONAL

Immunogenicity and Safety of 2 Doses of Avian Influenza A (H5N1) Vaccine Administered 3 vs. 8 Weeks Apart

This study is about a special vaccine called Arepanrix™ H5N1, which helps protect against bird flu. Recently, a specific type of bird flu (H5N1) has been found in animals in North America. This vaccine was approved in 2013, with two doses given at least 3 weeks apart. We don't have much information on how different time gaps between these two doses affect how well the vaccine works and if it causes side effects. So, this study will compare giving the two vaccine doses either 3 weeks apart or 8 weeks apart. The main goal is to find out which gap works best to make your body's defence system (immune system) strong against bird flu, and to check if the vaccine is safe either way. This research helps us understand the best way to use this vaccine for people who might be at risk of getting bird flu.

At a glance

Status

Active not recruiting

Phase

PHASE4

Sponsor

Canadian Immunization Research Network

Enrolment target

312

Start

14 Oct 2025

Estimated completion

30 Sep 2027

H5N1 Influenza H5N1 Virus Avian Influenza Avian Influenza A Virus

What is this study about?

This study is looking into a vaccine developed to protect against a type of bird flu called H5N1. Recently, this specific type of bird flu has been spreading among birds and some animals in places like North America. Because of this, Canada has made sure to have a supply of this vaccine, called Arepanrix™, ready in case it's needed for people who are at a higher risk of being exposed to bird flu.

This vaccine was given the green light for use back in 2013. The usual way to give it is in two doses, with at least three weeks between the first and second dose. However, we don't have a lot of information about whether giving these two doses with different time gaps in between might change how effective the vaccine is or if it leads to different side effects. This study aims to fill that gap by comparing two specific timeframes: giving the second dose either 3 weeks or 8 weeks after the first.

By doing this, researchers hope to learn whether one timing is better than the other for building a strong immune response against bird flu and ensuring the vaccine is well-tolerated. This information is crucial for public health, as it helps determine the most effective and safest way to use this vaccine if there's a need to protect people from H5N1 bird flu in the future.

Key takeaways

The study is about an H5N1 bird flu vaccine called Arepanrix™.
It compares giving vaccine doses 3 weeks apart vs. 8 weeks apart.
The goal is to find the best timing for vaccine effectiveness and safety.
Participants must be 18-59 years old and generally healthy.
Ensuring safety and efficacy for potential future public health needs is key.

Who may be eligible?

To join this study, you need to be generally healthy and aged between 18 and 59 years old. This means you haven't recently developed a new long-term illness or had an existing one get worse in the three months before getting the vaccine.

You also need to be able to follow all the study instructions and sign a consent form to show you understand and agree to take part.

If you could become pregnant, you need to be using reliable contraception for 28 days before the first vaccine dose and continue using it for 60 days after your last vaccine. You'll also need a negative pregnancy test on the day of vaccination. Reliable contraception includes methods like hormonal pills, patches, implants, IUDs, or having a male partner who has had a successful vasectomy and is your only sexual partner. If you've been abstinent, you must state this and commit to it for the study duration.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 18 and 59 years old?
Are you generally healthy, without recent new illnesses or worsening of long-term conditions?
Are you able to follow study instructions, including attending appointments?
If you could become pregnant, are you willing to use reliable contraception and follow pregnancy testing requirements?

Answer every question to see your result.

What does participation involve?

The detailed information for participation was not provided, so I cannot generate this section accurately. Please provide details on visits, assessments, medication, follow-up, and total duration.

Potential risks and benefits

Taking part in any study has potential benefits and risks. While this vaccine has been approved, this study is looking at how different timing for doses affects its protection against bird flu. You might help researchers understand the best way to use this vaccine, which could benefit others. As with any vaccine, there's a chance of side effects, which are usually mild like a sore arm or feeling a bit unwell. You'll be closely monitored, and you have the right to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (4)

Vaccine Evaluation Center
Verified postcode
Vancouver, Canada
Canadian Center for Vaccinology
Verified postcode
Halifax, Canada
Vaccine Study Centre of the McGill University Health Centre
Verified postcode
Pierrefonds, Canada
CHU de Québec
Verified postcode
Québec, Canada

Common questions

What is H5N1 bird flu?

H5N1 bird flu is a type of influenza virus that mainly affects birds, but can sometimes spread to humans and other animals.

What is the purpose of this study?

This study aims to find the best timing (3 weeks vs. 8 weeks apart) for two doses of the H5N1 bird flu vaccine to make sure it works well and is safe.

Who is the Arepanrix™ vaccine for?

This vaccine is intended for people who might be at a higher risk of being exposed to the H5N1 bird flu virus.

Will I get the actual vaccine?

Yes, all participants in this study will receive the H5N1 vaccine, Arepanrix™. No one will receive a dummy treatment (placebo).

Can women who could become pregnant join?

Yes, but they must use reliable contraception for a specific period before, during, and after the study, and have negative pregnancy tests.