New COVID-19 subvariants become the dominant strains in Canada

FILE - James Robson, a biomedical engineering graduate student, holds a swab and specimen vial in the new COVID-19, on-campus testing lab, Thursday, July 23, 2020, at Boston University in Boston. (AP Photo/Charles Krupa, File)

More than four years after COVID-19 effectively shut down the world, two new variants of the novel coronavirus have become the dominant strains in Canada.

These new subvariants, known as KP.2 and KP.3, are under the Omicron umbrella, a type of mutation from the COVID-19 virus itself. They've spread so quickly that, as of May 19, 49.2 per cent of COVID-19 cases in Canada involve one of the strains.

But how much of an effect do these subvariants have on the human body? Dr. Isaac Bogoch, an infectious diseases specialist at Toronto General Hospital, says while it's too early to tell, the likely scenario is that the impact of the virus will depend on each person.

"It's going to cause predictable symptoms, just like the other sublineages of Omicron," Bogoch said in an interview with CTVNews.ca. "Some people will have more serious infection, some will have a milder infection, and some will have no symptoms at all."

Bogoch, who is also an associate professor at the University of Toronto's faculty of medicine, says factors like age, health and underlying medical conditions coming into play.

He also says the current set of vaccines continue "to do a remarkable job in reducing the risk of serious infection," so while the most recent boosters don't account for these new variants, they still protect those who are most vulnerable.

However, there's no indication in the first few months the subvariant has been around that Canadians or public health officials should be worried.

"The first Omicron wave was terrible, back in late 2021 and early 2022," he said. "But subsequent Omicron waves have had fewer and fewer impacts on our health-care system and on our society.

"Of course, that's not to minimize the significance of COVID. It's terrible and certain populations are very much at risk," he continued. "(Both federal and provincial) public health can do a lot of good by having clear, open, transparent conversations with the general public, just discussing what the current state of COVID-19 is."

Similar to the last few years of COVID-19 and flu seasons before 2020, cases have been relatively low in the spring and summer before picking up in autumn and into winter. Bogoch expects the National Advisory Committee on Immunization, Canada's leading group in guiding the use of vaccines, to come up with guidelines in the fall, with new COVID-19 vaccinations rolling out around the same time as ones for influenza.

While Canadians have begun to settle into life after years of pandemic restrictions, there's a cautious optimism that comes in a post-COVID world.

"I think we're settling into something that's a bit more predictable," Bogoch said. "But I still think we have to be humble and recognize there's a lot we need to learn about this virus."