The COVID-19 virus keeps evolving. These 'disease detectives' are on the case
Researchers look for mutations in the virus's genetic code that might offer a growth advantage
The Omicron variant of the virus that causes COVID-19 was last year's unpleasant holiday surprise. More than a year later, a loosely knit group of "disease detectives" across Canada continues to keep watch for key mutations.
Officials with the World Health Organization (WHO) say Omicron is better able to pass from person to person than previous versions of the virus.
And so researchers have shifted their attention to Omicron's offspring.
"Are we ready to take the hit of another wave of a new variant that might emerge? I don't think so," Mike Ryan, the WHO emergencies chief, said of China's latest outbreak at the agency's last scheduled news conference of the year on Dec. 21.
Researchers look for mutations in the genetic sequence of the virus that might offer a variant a growth advantage over previous versions, cause more severe illness or help it to get around our immune defences.
"Omicron, the latest variant of concern, is the most transmissible variant we have seen so far, including all the subvariants that are in circulation, more than 500 of them. So we will continue to see surges of infection around the world," said Maria Van Kerkhove, WHO's technical lead for COVID-19.
It's critical to continue to monitor known variants, as well as being able to detect new ones, so that strategies can be adjusted if needed, she said.
Like a wolf in sheep's clothing
To Canadian variant tracker Fiona Brinkman, mutations in genetic sequences of SARS-CoV-2 offer important clues to identify trends and detect new clusters of cases or outbreaks.
"These viral sequences tell a little story about what's happening right now that give us a hint about what the story will be to come," said Brinkman, a professor of molecular biology and biochemistry at Simon Fraser University.
"You're taking this data and then trying to be a detective."
When the virus mutates to something that's harder for our immune system to recognize, then it's harder to fight an infection.
"It's literally like a wolf putting on sheep's clothing," Brinkman said.
Brinkman and her team are currently tracking "a whole soup of variants," in part to predict what might happen so health-care officials can plan staffing amid ongoing shortages, overrun emergency departments and a lack of primary care.
"How big is that impact going to be in January, after the holiday season?" Brinkman asked. "We wouldn't be surprised if we see a bump in cases."
On the lookout for major new variant
Elsewhere in the country, Art Poon calls himself a scientist who specializes in tracking viruses — how they evolve and how they spread. His day job focuses on HIV.
Scientists use "molecular bread crumbs" left by the virus to figure out where COVID has moved between countries, he said.
"We would be looking for a rapid increase in the number of infections," said Poon, an associate professor of virus evolution and bioinformatics at Western University in London, Ont. "Is it spreading faster than we would expect?"
But the decline in testing and sequencing for the virus means we're "driving blind" in trying to make accurate predictions, said Brinkman.
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Poon, Brinkman and dozens of other trackers across Canada meet weekly, virtually, applying their computational and modelling skills to COVID-19. They also share their sequencing findings with international counterparts.
It's important to realize that there's "no big new variant" that we're seeing right now, Brinkman said.
"That doesn't mean one won't occur. One of the important components about this work is to really catch those new variants that are really significant as soon as possible."
The COVID-19 picture in Canada is increasingly unique in the world, given differences in when Omicron hits and how hard, as well as varying degrees of immunity from vaccinations.
"Surveillance within Canada is going to become very important," Brinkman said. She advocates for surveillance here, because it's now harder to apply what's happened elsewhere in order to make predictions for Canada.
National data from the federal government's COVID-19 Immunity Task Force suggests more than 70 per cent of people across the country have been infected. While there was a large jump in infections during Omicron waves in 2022, fewer of those aged 60 and older show protection from antibodies following infection.
Beyond COVID-19, Brinkman hopes to apply the tools scientists have developed during the pandemic to study other troublesome infections, like influenza.
"We are definitely going to be seeing new variants," Brinkman said. "Whether that's going to be COVID or whether that's going to be flu is another story."
As multiple respiratory infections like COVID-19, influenza and respiratory syncytial virus (RSV) continue to sicken Canadians and further stretch our health-care system and medical staff, Brinkman shared preventative advice backed by public health data.
"One of the best masks you can wear is a recent vaccine shot," she said.
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With files from CBC's Christine Birak