We're in the middle of flu season and a new variant of COVID-19 is making its way across Canada.

The XEC strain, a hybrid of the Omicron subvariants KS.1.1 and KP.3.3, was first discovered in Canada in mid-August and the number of COVID-19 cases with the XEC variant has increased rapidly.

According to the latest data from the Public Health Agency of Canada, the proportion of positive cases with the XEC variant was 18.9 per cent as of October 13, up from just 3.1 per cent of cases on September 1. Most cases are about the Omicron KP.3.1.1 variant, which accounts for 48.4 percent of all COVID-19 cases.

Isaac Bogoch, an infectious disease specialist at Toronto General Hospital, says it's normal for the virus to mutate into different variants.

“We have seen several variants over the last almost five years,” Bogoch said. “It just means the virus is changing as expected. I think when people wonder what that actually means, it's always difficult to predict the future. But the coming winter will likely look a lot like last winter due to COVID-19 disease.”

Does the new vaccine protect against XEC?

Health Canada approved Pfizer-BioNTech's updated COVID-19 vaccine in September, which is now available for use across the country.

However, it was developed before the XEC variant became available to the general public.

Bogoch said the latest vaccine was developed for a subline of Omicron called KP.2, which began circulating a few months ago. While it may not be perfect for combating the XEC strain, he says any new updated vaccine will be more similar to the circulating mutations of the COVID-19 virus.

“There will always be an arms race where the virus mutates and a vaccine is developed to adapt to it,” Bogoch said, adding that it is very similar to the influenza vaccine, which is updated every year. “You’ll never get it perfect.”

Bogoch says that since the start of the pandemic, regardless of the vaccine and the active strain of COVID-19 circulating, all vaccines have “done a remarkable job of reducing the risk of serious infections such as hospitalizations and deaths.” for those who are most at risk.

“It doesn’t have to be a perfect match, but we know the vaccines are still pretty darn good.”

Bogoch says even as we move past the era of mandatory masks, people can choose to wear a mask indoors to reduce the risk of illness and that people should, if possible, stay home if they are sick, to prevent others from getting sick too.