Canada racing toward influenza peak, and what’s next for avian flu: The latest on respiratory virus season for week of Feb. 24

Canada’s colder weather goes hand-in-hand with respiratory virus season, with flu, RSV and COVID-19 circulating. While Canadians learned a lot about how to protect themselves from illness during the height of the pandemic, new information released by health care practitioners can help inform decisions, including the availability of flu shots.

We’ll be publishing an update on respiratory virus season at the beginning of each week. Looking for more information on the topic that you don’t see here? E-mail audience@globeandmail.com to see if we can help you.

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The latest news:

• Canada is racing toward a peak in influenza cases with nearly 27 per cent of tests having come back positive in the third week of February, according to the Public Health Agency of Canada’s respiratory virus surveillance report. The agency, in its update on Friday, said “continued increase is possible.” The average peak positivity for flu from 2014-15 to 2019-20 was 31.3 per cent.
• Down, down, down go cases of COVID-19 and respiratory syncytial virus, or RSV, across the country. RSV dipped to a positivity rate of roughly 5 per cent, from 5.9 per cent the week prior, while COVID dwindled by half a percentage point to 4 per cent.

Outlook on RSV, COVID-19 and flu in Canada:

• Nearly 12,000 cases of the flu were detected across Canada in the week ending Feb. 15, with a positivity rate of 26.9 per cent. Widespread activity was reported in 11 regions in four provinces: Alberta, British Columbia, Ontario and Quebec. The territories, however, had the highest positivity percentage for flu at 36.5 per cent, followed by 34.2 per cent in Quebec and 32.3 per cent in B.C.
• COVID activity is higher in the eastern half of Canada than in the west. Newfoundland and Labrador had the highest positivity rate at 7.7 per cent; its Atlantic counterparts Prince Edward Island and Nova Scotia also recorded rates between 5 and 7 per cent. Ontario’s rate was 6.6 per cent.

The evolution of avian flu and what comes next:

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Last week, The Globe and Mail’s health science reporter Jennifer Yang spoke with Dr. Richard Webby at St. Jude Children’s Research Hospital in Memphis, Tenn., about the evolution of avian flu and where we stand today. Below, Jennifer answers some of our most pressing questions on the highly contagious virus.

As you mentioned in your piece, avian influenza has become practically impossible to ignore. How worried should people be?

I’ve also been struggling to calibrate my personal worry meter, which is why I was so eager to pose this exact question to an expert like Dr. Webby, who’s been studying H5N1 for decades. But it’s a tough one to answer, even for him.

He said the risk remains low for the vast majority of people as today’s version of H5N1 is pretty bad at infecting humans. But he pointed to a constellation of troubling factors. There’s a lot of H5N1 virus circulating now, including in mammals that had never been infected before, like cows. This means the virus has way more opportunities to mutate and improve its ability to infect humans.

A recent scientific paper suggested that even a single mutation could give the virus the boost it needs to become more proficient at infecting humans. And recent human cases, such as that of the B.C. teen last year, did show worrying mutations in virus samples taken from the patients, though luckily those strains didn’t seem to spread any further.

Bottom line: the risk to most people is super low right now. But there’s no telling how the virus might shapeshift next month – or even next week.

Avian flu has not yet been detected in Canadian dairy cattle but herds have been infected in other countries, including the United States. Can you tell us why this is concerning?

Bird flu experts were stunned when H5N1 jumped into dairy cows last year and caused an outbreak. This had never happened before.

The long-standing worry has been that once H5N1 got into a mammal population, it would start picking up mutations that make it better adapted to humans. Thankfully, this doesn’t seem to have happened yet, though the U.S. dairy cow outbreak continues to spread. As of Feb. 21, nearly 1,000 infections have been confirmed in cattle across 17 states; those numbers will only continue to grow.

What are experts paying close attention to in the coming months?

Dr. Webby will be watching for those key mutations that help the virus infect humans more effectively. He actually expects to see these mutations eventually popping up; it’s just the nature of this virus to keep evolving. He said his “worry meter will really start to shake” if those versions of H5N1 actually start to spread.

To read Jennifer’s full interview, click here.

Hospitalizations for COVID-19, RSV and flu:

• More than 2,400 flu-related hospitalizations have been recorded in Canada since last August, including 252 during the third week of February, according to PHAC. Roughly 200 cases have required admission to intensive-care units since last August and 104 people have died.
• COVID-19 infections have sent nearly 4,285 people to hospital since the start of the season with 311 cases requiring intensive care. More than 900 people have died, the majority of whom were 65 and older. PHAC does not have any data on severe outcomes related to RSV this season.

How to protect yourself and your loved ones from respiratory viruses:

• Respiratory viruses can spread from person to person or through contact with contaminated surfaces or objects, such as phones, door handles or elevator buttons. To protect yourself and others, Health Canada recommends wearing a well-fitted respirator or mask, getting vaccinated, washing your hands regularly, cleaning high-touch surfaces, improving indoor ventilation and covering your mouth when sneezing or coughing. People are encouraged to stay home when sick.

Seasonal shots:

Flu and COVID-19 shots are available across the country. It is safe to receive both vaccines at the same time. Immunization information for all provinces and territories can be found here:

• Alberta
• British Columbia
• Manitoba
• Newfoundland
• New Brunswick
• Northwest Territories
• Nova Scotia
• Nunavut
• Ontario
• Prince Edward Island
• Quebec
• Saskatchewan
• Yukon