NCT07275060

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

Immunogenicity and Safety of 2 Doses of Avian Influenza A (H5N1) Vaccine Administered 3 vs. 8 Weeks Apart - A Multi-Center Non-Inferiority Placebo-Controlled Observer-Blinded Phase 2 Randomized Controlled Trial

• Status: Active Not Recruiting
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 312 (estimated)
• Sponsor: Canadian Immunization Research Network · Network
• Sex: All
• Age: 18 Years – 59 Years
• Healthy volunteers: Accepted

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).

Conditions

• H5N1 Influenza
• H5N1 Virus
• Avian Influenza
• Avian Influenza A Virus

Interventions

Type	Name	Description
BIOLOGICAL	H5N1 vaccine (Arepanrix)	The H5N1 (Arepanrix) vaccine will be administered according to the Product Monograph.
OTHER	Saline (as a placebo)	Normal saline will be administered as a placebo according to the Product Monograph.

Timeline

• Start date: 2025-10-14
• Primary completion: 2027-02-28
• Completion: 2027-09-30
• First posted: 2025-12-10
• Last updated: 2026-01-16

Locations

4 sites across 1 country: Canada