New Omicron subvariant BA.2.75 detected in Canada

A new Omicron subvariant that is driving infections in India has been detected in Canada.

Known as BA.2.75, the coronavirus mutation has been found across India and in smaller numbers in at least 10 other countries, including Australia, Germany, the United Kingdom, the U.S. and Canada.

"As of July 6, it is estimated there are 5 detections of BA.2.75 in Canada based on the preliminary definition," a Public Health Agency of Canada spokesperson told CTVNews.ca. "These numbers may change as the definition of this sub-lineage is clarified."

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While BA.2.75 is thought to be highly contagious and capable of dodging vaccines and immunity from previous infections, it is still unknown if it causes more serious disease than other variants.

"It's still really early on for us to draw too many conclusions," Matthew Binnicker, director of clinical virology at the Mayo Clinic in Rochester, Minn., told the Associated Press. "But it does look like, especially in India, the rates of transmission are showing kind of that exponential increase."

Several mutations separate BA.2.75 from its COVID-19 cousins. According to Binnicker, some of those could allow the virus to more efficiently bind to cells and escape antibodies.

First detected in May 2022, the World Health Organization (WHO) announced it was tracking the subvariant earlier this month.

"In Europe and America, BA.4 and BA.5 are driving waves," WHO director-general Tedros Adhanom Ghebreyesus said during a July 6 media briefing. "In countries like India a new sub lineage of BA.2.75 has also been detected, which we’re following."

The WHO currently lists BA.2.75 as a variant that’s "under monitoring." As of July 12, approximately 74 per cent of cases sequenced in Canada were BA.5.

"As with all new sub-lineages of COVID-19, scientists from the Public Health Agency of Canada (PHAC), along with national and international experts, are actively monitoring and evaluating these Omicron sub-lineages and their associated studies," the Public Health Agency of Canada spokesperson said. "When compared to BA.2, preliminary international reports have shown that BA.5, BA.4 and likely BA.2.75 have increased transmissibility and ability to potentially partially evade immune protection by prior infection and/or vaccination if it has waned over time,"

In Canada and many other countries, COVID-19 surveillance has dropped significantly in recent months, meaning true case numbers are likely much higher than official figures.

Although vaccines and boosters might not prevent COVID-19 infection, Canadian officials say they are still a strong defence against severe disease.

"Evidence indicates that the vaccines used in Canada are very effective at preventing severe illness, hospitalization and death from COVID-19," a government website says. " A booster dose following a primary series of mRNA vaccines offers better protection against Omicron infection and severe disease than the primary series alone."

With files from the Associated Press