Canadian officials consider ‘pre-pandemic’ H5N1 bird flu vaccines

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As H5N1 bird flu spreads rapidly through livestock and other animals in the US, Canadian officials are exploring the possibility of stockpiling “pre-pandemic” H5N1 vaccines as a precaution.

Highly pathogenic avian influenza (H5N1) has not been detected in any Canadian livestock and the risk of transmission to the general public is considered low, but the recent rapid spread of the virus through livestock and elsewhere in the U.S. The US has public health officials from around the world. world on high alert.

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Health experts urge people not to drink raw, unpasteurized milk and to make sure meat is cooked thoroughly, but they say the real potential risk of bird flu comes not from the food, but from the possibility that changes in the virus allow it to jump. from animals to humans. That could create a possible influenza pandemic because human immunity to the virus is expected to be minimal.

Unlike the United States, Canada has no stockpile of H5N1 vaccines, according to the Public Health Agency of Canada (PHAC). But it does have arrangements for rapid access to pandemic influenza vaccines if needed, said Nicholas Janveau, a PHAC spokesman.

“PHAC maintains agreements to ensure timely access to pandemic influenza vaccines for the entire Canadian population in the event of an influenza pandemic,” he said.

Those agreements should protect against the risk of vaccine embargoes, border closures and delays in transportation and shipments, “as seen recently during the COVID-19 pandemic,” he said.

PHAC is currently considering evaluating options for producing pre-pandemic H5N1 vaccines that could be available in the event of a pandemic declaration. The ability to do so is part of an agreement with its primary pandemic influenza vaccine provider, part of Canada’s influenza pandemic preparedness plan.

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It is also assessing the risks of H5N1 and has processes in place to shift annual influenza vaccine production from seasonal influenza vaccine to pandemic influenza vaccine.

There are also stockpiles of antiviral drugs maintained by the federal government as well as provincial and territorial governments for use during an influenza pandemic, Janveau said. Antivirals are medications that fight the virus in your body.

In recent days, US health officials have reported outbreaks of H5N1 avian influenza in at least 33 dairy herds, as well as poultry and wild birds. A person working with dairy cattle became infected and there have been widespread reports of barn cats becoming ill and dying.

The discovery of traces of the H5N1 bird flu virus in about 20 percent of retail milk samples tested in the United States has caused growing concern that outbreaks in livestock are more widespread than initially believed. . The virus fragments were not live and pose no risk, officials say, but they suggest there are more infected cows than have been reported, raising the risk of mutations that could allow the virus to successfully jump to humans.

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That’s the kind of scenario epidemiologists have studied for a long time, said Raywat Deonandan, an epidemiologist and professor at the University of Ottawa.

“We’re all taught this in epidemiology school,” he said. “For 20 years, flu watchers like me have been warning about the jump (to humans) of bird flu.”

But Deonandan noted that, despite circulating for decades, this bird flu virus has not made the jump to humans to allow widespread human-to-human transmission. Globally, there have been 26 human cases associated with the current H5N1 strain that is circulating. Human cases have mainly occurred through close contact with infected birds or animals.

Deonandan noted that governments are also preparing for the possibility of a flu pandemic, even if one does not materialize. Some of the lessons learned from the COVID-19 pandemic should improve the response to any future pandemic, she said.

“There’s a lot of good news here.”

Seasonal influenza vaccines are produced in Canada and elsewhere each year based on an assessment of the influenza strains most likely to circulate in the following fall and winter. According to the U.S. Centers for Disease Control, it takes at least six months to produce a large amount of flu vaccine.

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PHAC says it continues to “evaluate the risks of H5N1” and has a process to shift vaccine production from seasonal influenza vaccine to pandemic influenza vaccine.

It also has a comprehensive surveillance system to monitor influenza activity and human H5N1 cases should they arise.

“As influenza viruses constantly change and cases in livestock increase the opportunities for changes leading to mammalian adaptation, continued surveillance and preparedness are critical,” Janveau said.

In an assessment published Friday, the World Health Organization said human-to-human transmission is unlikely at this time without further genetic changes to the virus, but as viruses constantly evolve, the WHO called on countries to increase surveillance.

“As these viruses constantly evolve and spread in animal populations, and with increased risk of exposure to humans, there is a continued need to reassess risks as the situation evolves and as more information becomes available.”

Meanwhile, the Canadian Food Inspection Agency said that since the virus has not been detected in Canadian cattle, it is not testing raw or unpasteurized milk.

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“HPAI (highly pathogenic avian influenza) is not a food safety issue as pasteurization is a requirement for the sale of cow’s milk in Canada. “This process kills harmful bacteria and viruses while preserving the nutritional properties of milk, ensuring our dairy products are safe to consume,” the CFIA said in a statement.

Meanwhile, Deonandan said H5N1 has pandemic potential “but a lot of things have pandemic potential.” He noted that unlike COVID-19, vaccines will be available, although there will likely be high demand for them, leaving an equity gap for poorer countries. Antivirals will also be available.

But, he said, it is likely to be hard on the elderly and children, which could lead to school closures or start a debate about it. Children under six months would also not be eligible to be vaccinated.

He said people should take precautions, such as staying away from raw milk and cooking food thoroughly, as well as avoiding dead birds and other wildlife. And he said Canada should start producing vaccines now.

“It is better to have it and not need it than to need it and not have it.”

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