Summary of NACI statement of February 19, 2025: Rapid response on preliminary guidance on human vaccination against avian influenza in a non-pandemic context as of December 2024 

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• Overview
• What you need to know
• Quotes

Overview

• On February 19, 2025, the Public Health Agency of Canada (PHAC) released the National Advisory Committee on Immunization's (NACI) Preliminary guidance on human vaccination against avian influenza in a non-pandemic context as of December 2024. This guidance is based on current evidence and NACI expert opinion.
• As of February 14, 2025, 68 human cases of avian influenza A(H5N1) were reported in the US since the start of 2024, primarily among dairy and poultry workers, while Canada reported one human case. Of these human cases, a small number have been severe, including the one case in Canada, and one death has been reported in North America (Louisiana, US). Most human cases can be traced to animal exposures, although some have had an unknown source of exposure.
• The number of human cases of avian influenza A(H5N1) in North America is increasing, primarily among poultry and dairy farm workers. Some Canadians may face increased risk of exposure to H5N1 viruses due to occupational hazards (e.g., poultry and dairy farm workers, laboratory workers); however, the risk to most Canadians remains low at this time.
• This NACI guidance offers a preliminary framework to advise Canadian provinces and territories (PTs) on whether to use human vaccines against avian influenza (HVAI) in a non-pandemic context, centered on the objective to prevent human infection with avian influenza A(H5N1) viruses. Preventing transmission from animals to humans will help to prevent severe disease in humans and could also help limit opportunities for viral adaptations that could facilitate human-to-human transmission.
• In the event that PTs determine it is necessary to start offering HVAI, NACI has identified key populations to consider prioritizing for vaccination including laboratory workers handling live avian influenza A (H5N1) virus and people with ongoing contact with known infected animals or their environments. NACI has also provided product-specific advice to advise PTs on recommended use of HVAI should it be needed (e.g., recommended schedule, guidance on concurrent administration).
• Refer to the full NACI statement for the detailed guidance framework.

What you need to know

• Avian influenza H5N1 outbreaks on both poultry and dairy farms have increased in recent months both globally and in North America, and cases have been reported in humans. Among the human cases of H5N1 in North America, almost all have been reported in people with exposures to dairy cattle or poultry including in non-commercial settings. While the source of exposure is not known for a few North American H5N1 cases, no evidence of human-to-human transmission has been reported to date. Almost all cases in North America have also been mild, with only a few cases of severe disease or death.
• Many countries, including Canada, are boosting surveillance activities, securing access of human vaccines against avian influenza (HVAI), and preparing for the possible use of HVAI to prevent and respond to avian influenza A(H5N1) outbreaks.
• HVAI can be used proactively in a non-pandemic context to protect people who may be at increased risk of being exposed to the virus through animals.
• At this time, based on the available supply and what is known about the epidemiological situation, NACI has provided guidance to assist provinces and territories (PTs) in deciding if, when, and how to use HVAI.
• NACI has not recommended broad deployment of HVAI, but has identified considerations for when HVAI could be used for key populations. NACI has outlined scenarios where it could be appropriate for PTs to consider using an available vaccine supply based on the evolving epidemiology.
• NACI reiterates a strong recommendation for all individuals 6 months of age and older to receive an authorized, age-appropriate seasonal influenza vaccine to reduce the burden of seasonal influenza in Canada. This includes those likely to have significant exposure to avian influenza A viruses (e.g., H5N1) through interactions with birds or mammals. While seasonal influenza vaccines do not protect against avian influenza A(H5N1), they may reduce the severity of seasonal influenza and may potentially reduce the risk of co-infection with both seasonal and avian influenza strains.
• NACI will continue to monitor the evolving evidence and epidemiology of avian influenza A(H5N1) in animals and humans, scientific developments, and evidence on HVAI, and will update guidance as necessary.

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Quotes

"NACI has developed a framework to help make vaccine decisions as the epidemiology of avian influenza A(H5N1) continues to evolve. While it is not possible to predict exactly what will happen with this virus, the committee has identified some epidemiological scenarios and populations where human avian influenza A(H5N1) vaccine could be considered. NACI supports provinces and territories to work with federal public health leaders to assess which scenarios are occurring in Canada, and whether vaccine will become part of the public health response for those at high risk of exposure."

"I would like to thank the National Advisory Committee on Immunization (NACI) for their important and proactive efforts in providing this preliminary guidance on human vaccination against avian influenza A(H5N1). Although the current risk to the general population remains low, the evolving nature of avian influenza highlights the need for ongoing vigilance. Preparedness is key to ensuring that we are ready to respond to emerging health threats and protect our communities."