This flu season nothing to sneeze at

Concerns that this year’s flu shot may not be all that effective

The influenza season in Canada could be shaping up to be a potentially nasty one, with a mixed bag of viruses already circulating in much of the country, say infectious diseases experts.

There are also concerns that this year’s flu shot may not be all that effective in preventing the respiratory illness.

“There’s all kinds of speculation going on because of the experience in the Southern Hemisphere,” said Dr. Danuta Skowronski of the BC Centre for Disease Control, referring in particular to Australia.

“They had quite a substantial epidemic due to H3N2, so there’s a lot of speculation that that’s foreboding a severe season for us also,” she said from Vancouver.

H3N2 is a subtype of influenza A, viruses which tend to cause more severe disease in some segments of the population, specifically the elderly and young children.

RELATED: Flu season is here

At the end of its flu season in mid-August, Australia had more than 93,000 laboratory-confirmed cases — almost 2.5 times the number of infections and double the number of hospitalizations and deaths compared to the previous year, the country’s disease surveillance system reported.

“But we cannot say we will go on to experience the kind of severe season Australia had, in part because we ourselves had a fairly severe epidemic due to H3N2 in 2016-17,” Skowronski said. “And that may dampen down the contribution of H3N2 this season, which would be a good thing.”

However, Australia also experienced significant cases of influenza B, said Skowronski, and parts of Canada appear to be mimicking that pattern in the early months of the Northern hemisphere’s flu season.

In B.C., for instance, low levels of H3N2 infection have been confirmed since the beginning of the season in late August, but a strain known as B/Yamagata has also been found circulating within the population.

“And this is very early. We’re having about five times the amount of influenza B pickup during the autumn period in British Columbia than we typically have,” she said. “We don’t normally see this kind of influenza B uptick until February, so this is quite unusual.

“If this persists, there could be kind of a double-barrelled threat with B/Yamagata and influenza A/H3N2.”

In its weekly FluWatch report, the Public Health Agency of Canada says the annual sneezing-coughing season began early this year — especially with illness due to influenza B — and the percentage of laboratory-positive tests for flu is higher at this point on the calendar compared with previous seasons.

As of Nov. 25, almost 2,100 lab-confirmed cases had been detected in various parts of the country, of which 84 per cent were influenza A. Those infections resulted in 371 hospitalizations, including 21 ICU admissions, and eight deaths, the report says.

Dr. Allison McGeer, director of infection control at Mount Sinai Hospital in Toronto, said lab testing in Ontario is turning up ”quite a lot of B isolates, nearly as many Bs as H3N2.”

But she said it’s too early to predict what strain will predominate or how severe the season will be.

“This prediction ahead of time is a mug’s game, but I think it’s probably not going to be an H1N1 season,” McGeer said. ”But whether it’s going to be a B or H3N2 or mixed is still open.”

Added to that uncertainty is the question of how effective this season’s vaccine may be in preventing people from getting the flu.

This year’s shot is the same as the one used in 2016-17, containing components for three major strains: A/H1N1, A/H3N2 and B/Victoria, based on a recommendation by the World Health Organization made in February.

However, the shot does not provide exact matches for the H3N2 and the B strains now circulating, said Skowronski.

In the case of H3N2, the vaccine component has been genetically altered somewhat as a result of the manufacturing process, which involves growing vast quantities of the virus in eggs.

And the B strain circulating isn’t a Victoria lineage as predicted by the WHO, but a Yamagata known as B/Phuket.

Last year in Canada and the U.S., the vaccine was found to be only 35 per cent effective in preventing cases of H3N2 influenza, she said. And in Australia, which used the identical vaccine as Canada’s this past season, its effectiveness against H3N2 infection was far less – only about 10 per cent.

“So given that, particularly for the H3N2 component, the vaccine effectiveness we’re anticipating will be low,” predicted Skowronski.

RELATED: Flu vaccine effectiveness called ‘decent’

Despite those misgivings, she encourages the elderly and those with underlying heart and lung conditions or with suppressed immune systems, who are vulnerable to influenza and its complications, to get their shot to obtain ”all the protection you can get.”

Health-care workers and people whose close contacts have underlying medical conditions have additional impetus to get inoculated against the flu, she said.

“But for others, healthy young adults with no comorbidity and no close contacts with such conditions, it’s a personal choice. And this isn’t the season to be thumping the pulpit over that.”

Still, McGeer said there’s good evidence accumulated over time that getting the flu shot every year “is a safer and healthier thing to do for myself and better for my patients and my family.”

And while it may not work well against H3N2, she said it’s worth getting the shot for protection against infection with H1N1 and even the B strain (the B/Victoria components may offer cross-protection against B/Yamagata).

“Yeah, it’s not a great vaccine, but it’s a lot better than nothing.”

The Canadian Press

Like us on Facebook and follow us on Twitter.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Lee Porteous will be one of the performers at the Duncan Showroom’s storytelling event later this month. (Photo Submitted)
Duncan Showroom hosts storytellers series

Monthly shows will be broadcast live on YouTube

A freight train makes its way over the Black Bridge in Duncan, back when rail was still running on the E&N corridor. A new survey from Island Corridor Foundation found that there is still a large amount of support for getting trains up and running again. (Citizen file)
Big support for rail on Vancouver Island, survey finds

80 per cent of survey respondents believe a modern and revitalized rail system should be funded

B.C. NDP leader John Horgan releases his election platform, Vancouver, Oct. 6, 2020. (B.C. NDP photo)
Horgan fishes with Cowichan elders at Cowichan Valley campaign stop

B.C. premier talks mental health and addictions, universal income

Will Arquiett had 30 points in 53 games with the Caps last season. (Citizen file)
Cowichan Capitals continue making trades

Four players added in return for Arquiett and Morgan

“The area’s youth Scouting commissioner Brian Crockett, at the campground on the Bald Mountain Peninsula’s Camp Woodlands Scout/Guide Camp, which saw overnight campers and international radio communication, Saturday, Oct. 16.” (Lake Cowichan Gazette, Oct. 20, 2010/Tyler Clarke photo)
Lake Flashback: Scouting return, fish biting, and election looms

Remember these stories from Cowichan Lake?

In this photo provided by Shannon Kiss, smoke from the CalWood Fire billows, Sunday, Oct. 18, 2020, as seen from Gunbarrel, Colo. (Shannon Kiss via AP)
‘First guys out:’ western Canadian air tanker fleet busy despite drop in wildfires

CEO believes wildfires have become more dangerous in recent years as people live closer to where they start

The BC Ferries vessel the Queen of Oak Bay. (News Bulletin file photo)
‘Buy a boat,’ Horgan advises anti-maskers on BC Ferries

NDP leader John Horgan talks COVID-19 misinformation

Canadian and American flags fly near the Ambassador Bridge at the Canada-USA border crossing in Windsor, Ont. on Saturday, March 21, 2020. Restrictions on non-essential travel between Canada and the United States are being extended until at least Nov. 21. THE CANADIAN PRESS/Rob Gurdebeke
Non-essential travel restrictions at Canada-U.S. border extended to at least Nov. 21

The restrictions do not apply to those providing essential services in either country

Is it time to start thinking about greener ways to package cannabis?

Packaging suppliers are still figuring eco-friendly and affordable packaging options that fit the mandates of Cannabis Regulations

Jordan Naterer, 25, was last seen Saturday Oct. 10. He planned a hike in the Manning Park area, and has not been seen since. Photo Facebook.
Family devastated as search for missing Manning Park hiker suspended

‘It was an extremely difficult meeting with the parents when we had to tell them.’

Join Black Press Media and Do Some Good

Pay it Forward program supports local businesses in their community giving

FILE - Nathan Cullen speaks to media in Smithers, B.C., Friday, February 28, 2020. THE CANADIAN PRESS/Jonathan Hayward
Horgan, Cullen apologize for NDP candidate’s comments about Haida candidate

Nathan Cullen had made insensitive comments about Roy Jones Jr. Cheexial

The BC Ferries vessel the Queen of Alberni. (News Bulletin file photo)
UPDATE: More sailings cancelled after ferry breaks down

Queen of Alberni out of commission, BC Ferries revises schedules

Six Mile Beach outside Nelson is known for its perfect sand, clear water and unique sand spit. But the drowning death of a man in July has residents asking if the dangerous spot has become too popular. Photo: David Grantham/Kootenay Drone Services
Dangerous oasis: The fatal history of a popular Kootenay Lake beach

Six Mile Beach near Nelson is known for its unique sand spit. But locals have feared it for decades

Most Read