As bird flu takes hold in Canada, experts are urging preparedness

Health Canada has approved three flu vaccines that could be used if bird flu becomes a pandemic, the agency says.

The federal government also has an agreement with vaccine maker GSK for domestic vaccine production that could be accelerated if necessary, the Public Health Agency of Canada told The Canadian Press in an email.

There is no evidence that H5N1 bird flu would cause a pandemic, but experts urged preparedness – including increased flu surveillance, early detection and vaccine availability.

PHAC confirmed Wednesday that a B.C. teenager who was hospitalized last week is the first person to contract the H5N1 flu in Canada. It was not known how they were exposed, but the strain is linked to viruses found in flocks during an outbreak on poultry farms in B.C. The teenager was seriously ill in hospital on Tuesday.

Human-to-human transmission of H5N1 – a strain of highly pathogenic bird flu – is rare and there is no evidence of long-term transmission, experts say. The majority of human cases in the United States and around the world are due to contact with infected birds, farm animals, or wild animals.

But the more people are infected by animals, the more opportunities the virus has to mutate and spread between people, says Angela Rasmussen, a virologist at the University of Saskatchewan's Vaccine and Infectious Disease Organization (VIDO).

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“The longer a virus can gain evolutionary experience with a particular host species, it will continue to adapt to being in that host,” Rasmussen said.

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“One of those adjustments would potentially be increased transmission and increased transmission efficiency.”

Rasmussen said the Canadian government should build up a stockpile of H5N1 flu vaccines like the United States, rather than relying on agreements with manufacturers to supply them on demand.

Dr. Fahad Razak, an internal medicine specialist at St. Michael's Hospital in Toronto, agreed, noting that it would take three to six months to deploy an H5N1 vaccine under existing contracts.

“In the event that you had to start protecting people quickly, the ramp-up period could simply be too slow,” said Razak, scientific director of a provincial advisory table during the COVID-19 pandemic.

The Public Health Agency of Canada said by email that it is not stockpiling H5N1 vaccines because “the shelf life of the vaccines is only a maximum of 2 years.”

Razak countered that Canada does not need vaccine doses for the entire country.

Keeping enough H5N1 vaccines on hand to immunize people who are at high risk because they come into contact with potentially infected birds and animals, such as farm workers, could be “a middle-of-the-road approach,” he said.

Finland already offers H5N1 vaccination “to individuals at high occupational risk of exposure to avian flu,” said Dr. Matthew Miller, director of the Michael G. DeGroote Institute for Infectious Disease Research at McMaster University in Hamilton.

Miller said offering the shot to dairy workers, poultry workers or people who work with potentially infected wildlife to reduce their risk of exposure would also reduce the risk of a pandemic.

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“This is something that is being talked about in jurisdictions around the world,” Miller said.

When it comes to surveillance, PHAC says provincial and territorial public health agencies must report both “confirmed and probable” H5N1 cases within 24 hours. It said the National Microbiology Lab in Winnipeg can quickly test and detect human cases for jurisdictions that cannot test locally

The Canadian Food Inspection Agency has also tested milk for signs of H5N1 in dairy cows. There is no evidence yet of the virus in Canadian cows, but bird flu has ravaged many herds in the United States.

Razak also called for testing of wastewater – used during the COVID-19 pandemic – to revive bird flu.

British Columbia is actively looking for H5N1 in its wastewater, but Ontario halted its provincial wastewater testing program earlier this year.

PHAC conducts wastewater testing for seasonal flu in several cities and towns across the country, including Toronto. But it does not specifically monitor for H5N1 bird flu because it is “not possible to distinguish positive wastewater signals attributable to wildlife from human or animal sources,” the agency told The Canadian Press in an email.

That makes “it challenging to accurately interpret the results to inform the risk assessment and possible actions,” the report said.

Still, wastewater testing can be done at targeted locations where the majority of waste comes from humans, Razak said.

Shayan Sharif, professor of pathobiology at the University of Guelph's Ontario Veterinary College, said wastewater testing is useful as an “early warning process” regardless of whether it detects an animal or human virus.

“At least have it set up as some kind of screening system to identify it in real time as it happens,” Sharif said, noting that once H5N1 is detected, health officials can investigate to determine where it came from.

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