H5N1 Vaccine for Avian Flu

Not currently recruiting at 3 trial locations

Overseen By CIRN-Clinical Trials Network

Age: 18 - 65

Sex: Any

Trial Phase: Phase 4

Sponsor: Canadian Immunization Research Network

Must not be taking: Immunosuppressants, others

Disqualifiers: Pregnancy, Immunodeficiency, Bleeding disorders, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: 4

Duration: 8 weeks

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests different timings for the H5N1 vaccine (Arepanrix) shots to evaluate their effectiveness and tolerability. The vaccine targets avian flu, a virus that can spread from birds to humans. Individuals who have been healthy for the past three months and are not pregnant are eligible to participate. The trial compares administering the two vaccine doses either 3 weeks or 8 weeks apart, using a placebo (a harmless substance) for comparison. As a Phase 4 trial, this research aims to understand how the already FDA-approved and effective vaccine benefits more patients.

Do I need to stop taking my current medications to join the trial?

The trial information does not specify if you need to stop taking your current medications. However, if you are on immunosuppressant medication, you may not be eligible to participate.

What is the safety track record for the H5N1 vaccine (Arepanrix)?

Research has shown that the H5N1 vaccine, Arepanrix™, is generally safe and well-tolerated. Safety data from earlier trials indicated that most side effects are mild. People often experience soreness at the injection site or mild flu-like symptoms, which are common with many vaccines.

Studies also suggest that the vaccine remains effective over time. Even the oldest stored doses worked well without causing serious side effects.

Approved in 2013, Arepanrix™ has passed multiple safety checks, strongly indicating its safety for use. ^{1 2 3 4 5}

Why are researchers enthusiastic about this study treatment?

Researchers are excited about the H5N1 vaccine, Arepanrix, because it offers a targeted approach to preventing avian flu, a condition with limited vaccine options. Unlike most existing vaccines for seasonal flu, Arepanrix is specifically designed to combat the H5N1 strain, which is known for its potential to cause severe illness in humans. Additionally, the trial explores two dosing schedules, with one group receiving doses 3 weeks apart and another 8 weeks apart, to optimize protection and immune response. This flexibility could lead to more tailored vaccination strategies in the future, enhancing effectiveness and accessibility.

What is the effectiveness track record for the H5N1 vaccine (Arepanrix) for avian flu?

Research has shown that the H5N1 vaccine, Arepanrix™, is highly effective, with success rates between 86-100% in preventing bird flu. Approved in 2013, studies indicate it is generally well tolerated, with most side effects being mild. The vaccine enables the immune system to recognize and combat the bird flu virus upon exposure. This trial will examine how the timing between doses affects its effectiveness, with one group receiving doses 3 weeks apart and another group receiving doses 8 weeks apart. Overall, the vaccine has a strong track record of protecting against bird flu. ^{2 6 7 8 9}

Who Is on the Research Team?

Joanne M Langley

Principal Investigator

CIRN, Canadian Center for Vaccinology, Dalhousie University

Are You a Good Fit for This Trial?

This trial is for individuals at high risk of exposure to the highly pathogenic avian influenza A(H5N1). Participants must meet certain health criteria, but specific inclusion and exclusion details are not provided here.

Inclusion Criteria

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, 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

I haven't taken immunosuppressants in the last 6 months, except for short-term or topical steroids.

I haven't had a fever or serious illness in the last 24 hours.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive two doses of the H5N1 vaccine, administered either 3 or 8 weeks apart, with normal saline as a placebo at the alternate week.

8 weeks

4 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness, including seroprotection and adverse events, up to 12 months after the first dose.

12 months

Multiple visits (in-person and virtual)

What Are the Treatments Tested in This Trial?

Interventions

• H5N1 vaccine (Arepanrix)

Trial Overview

The study tests the immunogenicity and safety of two doses of Arepanrix™ H5N1 vaccine given either 3 or 8 weeks apart. The goal is to determine which dosing interval is more effective.

How Is the Trial Designed?

Group I: Group 2: H5N1 vaccines administered 8 weeks apart Active Control 2 Interventions

Two doses of the H5N1 vaccine administered 8 weeks apart Normal saline will be administered as a placebo at week 3.

Group II: Group 1: H5N1 vaccines administered 3 weeks apart Active Control 2 Interventions

Two doses of the H5N1 vaccine administered 3 weeks apart. Normal saline will be administered as a placebo at week 8.

Who Is Running the Clinical Trial?

Canadian Immunization Research Network

Lead Sponsor

Trials

12

Recruited

10,600+

Dalhousie University

Collaborator

Trials

177

Recruited

402,000+

Public Health Agency of Canada (PHAC)

Collaborator

Trials

51

Recruited

101,000+

Canadian Center for Vaccinology

Collaborator

Trials

12

Recruited

6,300+

CHU de Quebec-Universite Laval

Collaborator

Trials

177

Recruited

110,000+

IWK Health Centre

Collaborator

Trials

131

Recruited

112,000+

Vaccine Evaluation Center, Canada

Collaborator

Trials

3

Recruited

340+

McGill University Health Centre/Research Institute of the McGill University Health Centre

Collaborator

Trials

476

Recruited

170,000+

Citations

1.

pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC11002887/

Re-evaluating efficacy of vaccines against highly ...

In summary, this meta-analysis offers an updated and unbiased assessment evalution of avian influenza vaccine efficacy in poultry, demonstrating an efficacy ...

2.

wwwnc.cdc.gov

wwwnc.cdc.gov/eid/article/31/10/25-0668_article

Effect of Seasonal Influenza Vaccines on Avian ...

In this article, we demonstrate that immunization with commercially available human seasonal influenza vaccines also confers partial protection ...

3.

hpph.ca

hpph.ca/media/3awp4twv/hvai_fact_sheet-en_2025-06-26_final.pdf

Vaccine Fact Sheet: Highly Pathogenic Avian Influenza

Safety data from clinical trials and indirect evidence suggest that Arepanrix™ H5N1 is generally well tolerated. Most commonly reported side ...

4.

sciencedirect.com

sciencedirect.com/science/article/pii/S2590136225001032

H5N1 highly pathogenic avian influenza vaccination

Prediction of highly pathogenic avian influenza vaccine efficacy in chickens by comparison of in vitro and in vivo data: a meta-analysis and systematic review.

5.

dhpp.hpfb-dgpsa.ca

dhpp.hpfb-dgpsa.ca/review-documents/resource/SBD00280

Summary Basis of Decision for Arepanrix H5N1

Results from each of these reports showed a high level of effectiveness (86-100%) following vaccination with the Arepanrix H1N1 vaccine formulated with the A/ ...

6.

fda.gov

fda.gov/media/182543/download

Highly Pathogenic Avian Influenza (H5) Virus Vaccines

Safety and immunogenicity data supported the dose of antigen (90 ug/1 mL dose) and dosing regimen. (2 doses approximately 28 days apart) in ...

7.

cdc.gov

cdc.gov/bird-flu/situation-summary/index.html

H5 Bird Flu: Current Situation

H5 bird flu is causing outbreaks in wild birds and poultry, other animals and sporadic human cases.

8.

who.int

who.int/emergencies/disease-outbreak-news/item/2025-DON590

Avian Influenza A(H5N5)- United States of America

Existing seasonal influenza vaccines are unlikely to provide protection to against avian influenza A(H5) viruses, based on currently available ...

9.

pubmed.ncbi.nlm.nih.gov

pubmed.ncbi.nlm.nih.gov/30553570/

Safety and immunogenicity of influenza A(H5N1) vaccine ...

Stockpiled vaccines were well-tolerated, adverse events were generally mild, and there was no drop in immunogenicity to the oldest stockpiled A(H5N1) vaccine.