Understanding Canada’s Approach to Avian Influenza Vaccination
The National Advisory Committee on Immunization (NACI) has issued preliminary guidance on the use of human vaccines against avian influenza (H5N1) in non-pandemic situations. This proactive approach aims to safeguard Canadians as the global avian influenza outbreak continues to escalate.
With highly pathogenic avian influenza A(H5N1) spreading among wild birds, poultry, and mammals in Canada and the U.S., the risk of human exposure has increased. As of December 2024, there have been 61 confirmed human casesin the U.S., primarily among poultry and dairy workers, with one severe case. Canada reported a single severe case, with an unknown source of exposure.
In response, Canada—alongside European nations, the U.K., and the U.S.—has strengthened surveillance measuresand secured human vaccines for potential use.
Avian Influenza Vaccines Approved in Canada
Currently, two human vaccines against avian influenza H5N1 have been approved by Health Canada for individuals six months and older. Both are adjuvanted vaccines that require a two-dose series, administered 21 days apart:
1. Arepanrix H5N1 (A/Indonesia clade 2.1.3.2)
• Manufacturer: GSK
• Approved: 2013 (originally for pandemic use)
• Adjuvant: AS03
2. Foclivia H5N1 (A/Vietnam clade 1)
• Manufacturer: Seqirus
• Approved: 2021 (originally for pandemic use)
• Adjuvant: MF59
These vaccines have not yet been used in Canada but are expected to accelerate regulatory processes if a strain change is needed during a future pandemic.
Government Preparedness: Securing Vaccine Supplies
To bolster pandemic preparedness, the Canadian government has procured at least 500,000 doses of Arepanrix H5N1 (A/American wigeon). These doses will be allocated to provinces and territories in early 2025 for potential use.
This vaccine was authorized as a strain change from Arepanrix H5N1 (A/Indonesia) and is expected to be effective against clade 2.3.4.4b viruses.
Who Should Get Vaccinated? NACI’s Recommendations
In non-pandemic scenarios, human vaccines against avian influenza should be prioritized for high-risk groups, including:
1. Laboratory Workers Handling H5N1
• Those working in research, clinical, or industrial laboratories that manipulate live avian influenza viruses.
2. Individuals in Direct Contact with Infected Birds or Animals
• Farmers, poultry workers, and dairy workers on farms experiencing outbreaks.
• Wildlife officers, veterinarians, and rehabilitators handling infected animals.
• Culling teams involved in poultry or bird depopulation.
3. People on Farms Connected to Outbreaks
• Individuals working on farms in proximity to affected areas.
• Workers in primary control zones surrounding infected farms.
• Those with shared suppliers, equipment, or transportation links to infected farms.
4. Individuals in High-Risk Animal Environments
• Livestock workers, poultry processors, slaughterhouse workers.
• Wildlife researchers, rehabilitators, hunters, and trappers.
• People handling wild game or backyard flocks.
Vaccine Timing & Administration Guidelines
• NACI recommends an interval of at least six weeks between an avian influenza vaccine and any other vaccine(unless urgent).
• Arepanrix H5N1 (A/American wigeon) can be administered as a two-dose series for individuals six months and older, based on risk factors.
Future Updates on Avian Influenza Vaccination
NACI will continue to monitor avian influenza outbreaks, human transmission risks, and vaccine safety. As new scientific data emerges, recommendations may be updated accordingly.
Conclusion
The risk of avian influenza (H5N1) transmission to humans is growing, particularly among individuals exposed to infected birds, mammals, and contaminated environments. While Canada has not yet implemented mass vaccination, NACI’s preliminary guidelines ensure that high-risk populations can access human avian influenza vaccines if needed.
For ongoing updates on avian influenza prevention and vaccination, stay informed through Canada’s public health resources.