New Omicron subvariant could be problematic for immunocompromised

Scientists are keeping a close eye on a new subvariant of Omicron that is poised to become the dominant strain of COVID-19 this fall and winter.

Experts worry the subvariant BQ.1.1, which was first detected in Canada last month, could evade a well-known antibody drug and put vulnerable populations particularly at risk if the strain takes off in the fall.

Infectious disease specialist Dr. Isaac Bogoch says the subvariant could evade Evusheld, a treatment that is commonly given to transplant recipients and cancer patients. The drug is intended for people who cannot receive a typical vaccine or for whom vaccines alone won’t provide enough immunity.

“The problem with BQ.1.1 is that it has likely mutated to some extent where Evusheld won’t provide the same degree of protection,” Bogoch says. “That would be my main concern.”

Bogoch says we still do not know how much protection the new bivalent COVID-19 vaccine will provide against this new subvariant, but he says so far vaccines have proven effective at protecting most people from severe illness.

“Specifically for some of these sub-lineages of Omicron that are emerging, we don’t have data,” he says. “I think it’s pretty clear, any variant that has emerged we’ve seen these vaccines stand up against these variants.”

The new bivalent vaccine was made specifically for the BA.1 subvariant of Omicron, but health officials say the booster provides better protection against all Omicron variants. Health Canada approved the new shot from Moderna at the start of September.

Officials say with the start of the fall and winter respiratory illness season, vulnerable individuals such as those aged 70 and over, and moderately to severely immunocompromised individuals aged 12 and over are strongly recommended to receive their bivalent booster as soon as they can.

Health Canada says there will be enough supply of the shots for all Canadians 18 and older to get a dose this fall and winter.

Bogoch also recommends continued masking in indoor settings to help reduce the chances of infection.

Too early to tell if BQ.1.1 is growing in Canada

The Public Health Agency of Canada (PHAC) tells CityNews there have been 12 cases of the subvariant BQ.1.1 detected in Canada as of October 3. However, the real number is potentially much higher given that testing for the virus isn’t nearly as aggressive as it was compared to the beginning of the pandemic.

“PHAC is aware of BQ.1.1, a sub-lineage of Omicron that is a descendant of BA.5, and is monitoring it closely,” the agency said in a statement.

The BA.5 Omicron subvariant is the current dominant strain throughout much of the country.

PHAC says it is still too early to tell if the sub-lineage is growing within Canada.

With files from CityNews reporter Michelle Mackey