The federal government has purchased half a million vaccines designed to prevent H5N1 avian influenza — also known as “bird flu” — in humans.
The aim of the injections, says Health Canada, is to cut any risk of transmission to humans, especially among farm workers, medical staff and veterinarians. About 60 per cent of the doses will be distributed to the provinces, while the remaining 200,000 will be held in reserve.
The vaccine, GSK’s Arepanrix H5N1, is based on existing seasonal flu vaccine technology. It was approved in Canada on Feb. 19, the day the order was placed.
“Experts are concerned that Canada may be entering a dangerous period with migratory birds returning from their southern wintering grounds — carrying new mutations of H5N1 virus — while the human H1N1 flu season is still in full swing,” writes Oliver Dyer in a Feb. 24 article in the BMJ. “The swapping of viral genetic material in humans infected with both viruses simultaneously could lead to the formation of new strains, which combine the lethality of bird flu with the transmissibility of human flu.”
How has bird flu been transmitted to humans?
Dyer writes that H5N1 bird flu has infected more than 1,000 dairy herds in the U.S., as well as hundreds of chicken farms throughout Canada and the U.S. In the U.S., 69 people tested positive for the virus. However, 68 of them were infected with the variant circulating in U.S. cows, which resulted in unusually mild symptoms in humans.
“It is the only H5N1 flu variant known to cause mild disease in humans; across the world 54 per cent of the people who have contracted H5N1 flu have died,” says Dyer.
A Canadian teenager and an elderly American contracted a different H5N1 variant believed to have come from exposure to wild birds. The U.S. patient died.
The Canadian patient was in a B.C. hospital on respiratory support for two months before he was discharged from hospital. (He has not been publicly identified.)
Has the U.S. effort been affected by agriculture department firings?
Political developments south of the border are affecting how the U.S. Department of Agriculture (USDA) is coping with bird flu concerns.
A substantial number of the USDA’s bird flu workforce was fired on Feb. 14 on orders from Elon Musk’s Department of Governmental Efficiency as part of a government-wide purge.
“Although several positions supporting (the avian influenza program) were notified of their terminations over the weekend, we are working to rectify the situation and rescind those letters,” a USDA spokesperson told NBC.
How has H5N5 turned up in Canada?
A less well known H5N5 avian flu virus was detected recently on a non-commercial chicken farm in Newfoundland, where it killed all 34 birds.
Five other countries have reported the H5N5 virus so far in 2025: the U.K., Greenland, Germany, Iceland and Norway.
While the risk of infection for the public remains low, humans exposed to infected birds, mammals or contaminated environments face moderate risk.
What is Canada doing to contain the risk?
Canada is implementing several measures to contain the ongoing bird flu outbreak.
Enhanced surveillance:Canadian authorities are monitoring through wild bird surveillance, passive surveillance in domestic poultry, targeted surveillance when bird flu is detected, and pre-slaughter surveillance in commercial poultry.
Quarantine measures: Eight poultry farms in southern Ontario have been placed under quarantine since mid-December due to active infections.
Culling infected birds: Since 2021 more than 15 million birds have been culled in Canada to control the spread of avian influenza.
Restricting imports: As of Feb. 11, 2022, the Canadian Food Inspection Agency has restricted the import of bird by-products from certain regions with active outbreaks.
Public health involvement:Public health agencies are managing potential human impact, including reviewing and approving animal health and environmental decontamination plans in the wake of animal outbreaks. Public health units are required to follow up with close contacts of infected animals to reduce the risk of human illness and transmission.
Wastewater surveillance: The University of Ottawa’s wastewater lab is leading local surveillance to determine whether avian influenza is responsible for any influenza A infections detected in wastewater.
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