A new sub-lineage of the Omicron coronavirus variant is spreading across Europe at a concerning rate and 66 cases have been identified so far in B.C.
Scientists and health officials around the world are keeping their eyes on the descendant of the highly-transmissible variant that has been found in at least 40 countries.
Known as BA.2, scientists widely consider it to be stealthier than the original version of omicron because particular genetic traits make it somewhat harder to detect. Others worry it could also be more contagious.
In an emailed statement, the B.C. Ministry of Health told Vancouver Is Awesome that "BA.1 and BA.2 share many of the same mutations, but there are also mutations that are specific to each lineage."
Up to Jan 21., B.C. had detected 66 BA.2 cases in B.C., of which 33 were related to international travel surveillance.
Dr. Jeffrey Joy, Assistant Professor, Department of Medicine, UBC, told V.I.A. that there are several other sub-lineages of Omicron, including BA.1, BA.1.1, and BA.3.
"BA.1, BA.2, and BA.3 were all originally identified in southern Africa," he explained. "BA.2 and BA.3 share many but not all of the characteristic mutations in BA.1 and both BA.2 and BA.3 have many unique mutations of their own."
The professor notes that BA.1.1 and BA.2 are rising in frequency in some parts of the world and that "in some cases (for example Denmark) this is occurring after the first Omicron wave." However, health officials are still unsure of why they may be rising in frequency.
BA.2 also lacks some of the genomic features that made early cases of the Omicron variant easy to identify without whole-genome sequencing, he added. Early Omicron infections were identified via PCR dropout.
"BA.2 requires whole genome sequencing for identification. Therefore, jurisdictions that are no longer doing testing and epidemic surveillance by genome sequencing will not know if BA.2 is rising in frequency," he explained, adding that this "highlights the need for continued testing and genomic surveillance."
How fast is this BA.2 spreading and how much of a threat does it pose in Canada?
"In some places, it is displacing the original Omicron strains but it is early to say at this point how fast it is spreading relative to other sub-lineages," Joy noted. "It is possible that BA.2 and/or BA.1.1 could spur a rise in infections in Canada but difficult to predict at this point."
Since the Omicron variant emerged when Delta was the globally dominant strain, Joy highlighted that it is possible for "an entirely new variant" to cause a next wave in the pandemic. In other words, a spike in infections could stem from an entirely different part of the Sars-CoV-2 family tree outside of Omicron.
The World Health Organization classifies omicron overall as a variant of concern, its most serious designation of a coronavirus mutant, but it doesn’t single out BA.2 with a designation of its own. Given its rise in some countries, however, the agency says investigations of BA.2 “should be prioritized."
With files from the Canadian Press
