Overview

Avian influenza (commonly known as “bird flu”) is a type of influenza virus mainly found in wild birds, with cases of avian influenza in birds increasing during the spring and fall migration seasons.

Avian influenza can be classified two ways:

  • Low pathogenic avian influenza (LPAI)
  • Highly pathogenic avian influenza (HPAI)

“Pathogenic” refers to the ability of a virus to cause disease. Most avian influenza viruses are low pathogenic. These typically cause little or no signs of illness in infected poultry while highly pathogenic viruses can cause severe illness and death in infected poultry. In recent years the HPAI-H5N1 virus, which has been circulating in Ontario since 2022, has been detected in an increased number of wild and domestic animals worldwide. Based on circulation internationally, the H5N1 virus can cause disease in:

  • wild birds
  • commercial poultry
  • wild and domestic mammals, including some pets and dairy cattle in the USA
  • humans, in rare cases

At this time there is no evidence of sustained human-to-human transmission of avian influenza and the risk to the general public remains low.

Symptoms

Avian influenza is caused by a different virus that causes the seasonal flu, but some of the symptoms may be similar. Symptoms can range from very mild to severe, including:

  • fever
  • cough
  • sore throat
  • runny or stuffy nose
  • muscle or body aches
  • headaches
  • fatigue or tiredness
  • conjunctivitis (red eyes)
  • shortness of breath or difficulty breathing

Less common symptoms are:

  • diarrhea
  • nausea
  • vomiting
  • seizures

If you have symptoms and you have been exposed to an infected bird or mammal, you may be eligible for testing through Public Health Ontario.

It is important to tell your health care provider or contact Health811 if you have any of these symptoms and if you have been around sick or dead birds or animals in the past 10 days which were suspected or confirmed to have the virus.

Protect yourself

While the risk of catching avian influenza is low, you should always avoid handling live or dead wild birds. If you see a sick or dead bird, report it to the Canadian Wildlife Health Cooperative by phone at 1-866-673-4781 or online.

If contact is unavoidable, always:

  • wear gloves
  • use a doubled plastic bag for disposal
  • wash your hands after with soap and warm water

Food safety for people and pets

When handling food, you should always follow proper safe food handling practices.

Learn more about the safe handling and processing of wild game in the context of avian influenza.

Consumption of undercooked meat or unpasteurized milk products from animals that may be infected is not recommended for people or pets.

International travel

As an important measure before you travel outside of Ontario or Canada, visit the Public Health Agency of Canada’s website to determine if there are any active advisories for the region to which you are travelling.

While traveling there are some important precautions you should take to help safeguard your health, including:

  • avoiding visits to poultry farms or bird markets
  • not eating undercooked eggs, meat, or unpasteurized milk products
  • practicing proper hand hygiene through hand washing or bringing along an alcohol-based hand sanitizer

If you have a fever and respiratory illness within 10 days after returning from a region affected by avian flu, contact your health care provider, or Health811, immediately.

Immunization

While human infections of avian influenza are rare, a limited number of people in Ontario are currently eligible to receive the Arepanrix™ H5N1 vaccine to increase protection against infection with H5N1.

If you meet the eligibility criteria below you may be able to receive the vaccine. Contact your public health unit for more information.

Eligibility

Given their ongoing and significant occupational exposure to the H5N1 virus, a limited number of people are eligible for immunization to protect against infection if they:

  • have ongoing contact with birds or other animals likely to be infected with H5N1, such as:
    • wildlife officers
    • researchers
    • rehabilitators who handle dead or sick birds (for example, bird banders)
    • veterinarians or veterinary technicians who are exposed to dead or sick birds likely infected with avian influenza A(H5N1) (necropsy)
  • handle live avian influenza A(H5N1) virus in laboratory settings, such as:
    • laboratory workers who manipulate, handle, or culture live avian influenza A(H5N1) virus, such as in research, industrial or clinical reference laboratory settings

The Ministry of Health continues to monitor and assess the status of H5N1 in the province and globally, including continually reviewing available evidence and expert recommendations. Eligible populations may change over time as new information becomes available on the status of H5N1 in Ontario.

Those who are eligible can contact their public health unit for more information.

Vaccine administration

This H5N1 vaccine requires two doses. The second dose should be given at least three weeks (21 days) after the first.

It is preferred to wait at least six weeks after receiving a dose of the H5N1 vaccine before getting any other vaccine, including the seasonal flu shot, unless otherwise advised by a health care provider.

Eligible people who receive the H5N1 vaccine should still get their seasonal flu shot this fall. While the flu shot does not protect against H5N1, it can reduce the risk of infection with both the seasonal flu and avian influenza at the same time.

Vaccine safety

Health Canada has reviewed and approved the Arepanrix™ H5N1 vaccine for use for Canada, considering both safety and effectiveness.

Clinical trials of similar H5N1 products and use of similar products during the 2009 H1N1 pandemic have shown no safety concerns.

As a key component of vaccine safety, Ontario ensures ongoing monitoring of vaccine safety data in collaboration with local, provincial, territorial and national partners.

Pregnant or breastfeeding individuals

There is currently no direct data on the use of the Arepanrix™ H5N1 vaccine in those who are pregnant or breastfeeding.

Those who are pregnant or breastfeeding may consider receiving the vaccine after a risk/benefit discussion with a health care provider. Considerations may include personal risk of exposure and infection with H5N1 and the currently available data on the vaccine.

Who should not receive the vaccine

People who have serious allergies (anaphylaxis) to any ingredient in the H5N1 vaccine, except eggs, should not receive it. Studies have shown people who are allergic to eggs can safely receive influenza vaccines.

A health care provider can tell you which ingredients are in the vaccine and if it is safe for you.

Vaccine efficacy

The H5N1 vaccine is expected to provide protection against the currently circulating strain of H5N1 (clade 2.3.4.4b) and some cross-protection against related strains.

Vaccine side effects

Safety data from related clinical trials suggest that the Arepanrix™ H5N1 vaccine is generally well tolerated. The most reported side effects were:

  • mild to moderate reactions where the vaccine was injected
  • muscle aches
  • headache
  • fatigue (tiredness)
  • joint pain

If you develop any severe, unexpected, or unusual symptoms after receiving the H5N1 vaccine, whether you think they were caused by the vaccine or not, please report your symptoms to your local public health unit.

Severe allergic reactions are rare, but immediate medical care should be sought if symptoms occur, such as hives, facial swelling, or difficulty breathing.