Canada has detected BA.2 cases. What we know about this Omicron subvariant – National | Globalnews.ca

With signs of the COVID-19 Omicron wave having peaked in parts of the world, including Canada, scientists are keeping a close eye on a subvariant that is rapidly spreading in some countries.

The BA.2 sub-lineage of Omicron, which was first detected in November last year, was designated as a variant under investigation by the U.K. Health Security Agency (UKHSA) on Friday.

Read more:

Omicron FAQ: Everything you need to know about the COVID-19 variant

More than 10,000 cases have been reported in 47 countries, according to data by cov-lineages.org. So far, 51 cases of the BA.2 variant have been detected in Canada mainly from international travellers, the Public Health Agency of Canada (PHAC) confirmed to Global News on Tuesday.

“The virus is multiplying so much now globally that a new variant will pop up, and there are already subvariants related to the Omicron (variant),” said Dr. Horacio Bach, an infectious diseases expert at the University of British Columbia.

Story continues below advertisement

The Omicron variant of concern, B.1.1.529, has four sub-lineages: BA.1, BA.1.1, BA.2 and BA.3.

BA.1 accounts for the vast majority of the Omicron cases to date globally, according to the World Health Organization (WHO).

All viruses mutate and have subvariants that have a different genetic makeup than the original variant but have a common origin, said Levon Abrahamyan, a virologist at the University of Montreal.

Here is what we know so far about the BA.2 subvariant.


Click to play video: 'Is Omicron peaking in Canada?'







Is Omicron peaking in Canada?


Is Omicron peaking in Canada?

The BA.2 descendent lineage differs from the original Omicron strain BA.1 in some of the mutations, including in the spike protein, according to the WHO.

Story continues below advertisement

The BA.2 lineage has many similarities to BA.1 but does exhibit differences, including in some mutations that may affect transmissibility, detection and possibly immune escape, Anne Genier, a PHAC spokesperson, said.

Read more:

Omicron dims hope for achieving herd immunity against COVID-19, experts say

Early analyses suggest BA.2 has an increased growth rate compared to BA.1, the UKHSA said.

In Denmark, cases of BA.2 are rising rapidly, accounting for nearly half (45 per cent) of all Omicron cases in the country.

Norway, too, has seen a spike from seven detections on Jan. 4 to 611 on Jan. 19.

“This variant of the Omicron virus is growing strongly compared to the original Omicron virus, BA.1,” the Norwegian Institute of Public Health said in its weekly report.

“The properties of the virus are not known other than that it is more contagious than BA.1 and is also increasing in Denmark and Sweden, and may appear to be taking over BA.1 already.”

Story continues below advertisement

However, experts say additional research is needed to better understand how much more transmissible this subvariant is than the original Omicron.

“It looks like it’s infecting more aggressive[ly] compared to the regular Omicron, but it’s still under investigation and too early [to tell],” said Bach.

“If it is more transmissible, the vulnerable population will be impacted more,” he added.

The WHO said investigations into the characteristics of BA.2, including immune escape properties and virulence, should be prioritized independently to BA.1.

BA.2 has been dubbed the ‘stealth’ Omicron by some scientists because its genetic composition makes its harder to track in a polymerase chain reaction (PCR) test.

Story continues below advertisement

The UKHSA said that BA.2 lacks the genetic deletion on the spike protein which produces S-gene target failure (SGTF) in some PCR tests, which has been used as a proxy for Omicron cases previously.

Read more:

Omicron: How does it compare with other COVID-19 variants of concern?

Abrahamyan said it is not uncommon for PCR tests to miss infection or present a false negative, which can be due to the number of domains of the SARS-CoV-2 genome it is trying to detect.

To detect subvariants more efficiently, whole genome sequencing is usually done that can help identify all the mutations of the virus, he said.

Severity of illness and hospitalization

As an increasing number of cases are detected, BA.2 does not appear to cause more severe illness than BA.1.

Story continues below advertisement

But data is limited, according to Dr. Meera Chand, COVID-19 Incident Director at UKHSA.

Initial analysis by Denmark’s Statens Serum Instiut shows no differences in hospitalizations for BA.2 compared to BA.1.

“So far, the good news is that it seems that the rate of hospitalization, it doesn’t really differ a lot from the original variant of Omicron,” Abrahamyan said.


Click to play video: 'Canada’s COVID-19 hospitalizations still sharply rising amid Omicron-driven wave: Dr. Tam'







Canada’s COVID-19 hospitalizations still sharply rising amid Omicron-driven wave: Dr. Tam


Canada’s COVID-19 hospitalizations still sharply rising amid Omicron-driven wave: Dr. Tam

A growing body of research has shown that COVID-19 vaccines are standing up to the Omicron variant, at least among people who received booster shots.

Story continues below advertisement

Both Pfizer and Moderna are working to develop booster vaccines that can specifically target the Omicron variant.

Read more:

Omicron and vaccines: Experts break down the science behind COVID-19 jabs

Levon said it is most likely that those shots will also be effective against the subvariants.

Denmark’s SSI said analyses regarding vaccine efficiency are ongoing.

“It is expected that vaccines also have an effect against severe illness upon BA.2 infection,” the institute said.


Click to play video: 'Future of COVID-19 vaccinations: Will there be more boosters?'







Future of COVID-19 vaccinations: Will there be more boosters?


Future of COVID-19 vaccinations: Will there be more boosters?

View link »





© 2022 Global News, a division of Corus Entertainment Inc.

For all the latest health News Click Here 

Read original article here

Denial of responsibility! TechAI is an automatic aggregator around the global media. All the content are available free on Internet. We have just arranged it in one platform for educational purpose only. In each content, the hyperlink to the primary source is specified. All trademarks belong to their rightful owners, all materials to their authors. If you are the owner of the content and do not want us to publish your materials on our website, please contact us by email – [email protected]. The content will be deleted within 24 hours.