According to the World Health Organization, Omicron subvariants BA.4 and BA.5 are circulating at low levels in several countries in southern Africa and Europe.
The two sub-variants of the highly contagious Covid-19 strain have been discovered in Botswana, South Africa, Germany and Denmark, among others, WHO technical lead on Covid-19 Maria Van Kerkhove said Thursday.
BA.4 and BA.5 do not appear to be more contagious or deadly than the original omicron mutation so far, but that could change as more cases are discovered, she added. Van Kerkhove emphasized the need to maintain “robust” genome surveillance systems that would allow countries to monitor and analyze the two subvariants and earlier versions of omicron.
“It’s still early days. We need to make sure we can continue to track, share and analyze so we can answer questions like these,” Van Kerkhove said at a WHO briefing. that was streamed live on the organization’s social media platforms.
Her comments come days after the WHO said it was tracking several dozen cases of BA.4 and BA.5, in addition to previous omicron variants such as BA.1, BA.2, BA.3 and BA.1.1.
New wave of business
It also comes as the more contagious BA.2 subvariant spreads across different parts of the world, fueling a new wave of Covid cases after the unprecedented surge caused by the original omicron variant, BA.1, during the winter. BA.2 is now the dominant species worldwide. In the US, accounting for about 85% of new cases that have been sequenced, it is even more dominant in the northeastern region of the country, where it accounts for about 92% of new cases, according to data from the Centers for Disease Control and Prevention.
The earliest BA.4 sample was collected in South Africa on Jan. 10, but data shows the subvariant’s “accumulation of genomes” and geographic distribution is more recent, according to a UK Health Security Agency report released last week. released. By April 8, South Africa had reported 41 BA.4 cases, Denmark three cases, Botswana two and England, as well as Scotland, one each.
“While the total number of genomes is small, the apparent geographic distribution suggests that the variant is successfully transmitted,” the UK Department of Health said in a report.
The report also said there were 27 reported sequences of BA.5 on April 8, all of which were reported in South Africa between February 25 and March 25. But Botswana’s health ministry said on Monday it had identified both BA.4 and BA. 5 cases among fully vaccinated individuals ages 30 to 50, Reuters reported.
The WHO began monitoring BA.4 and BA.5 because they have new mutations “that need further study to understand their impact on the immune system’s escape potential,” according to Reuters.
Both subvariants have additional mutations in the spike region, part of the virus used to invade human cells, and unique mutations outside that region, according to a WHO report published Wednesday. Such mutations are associated with “potential immune escape characteristics,” the report said.
XE sub variant
Another ommicron subvariant that scientists call XE is also circulating at low levels in a number of countries.
XE is a “recombinant” variant that occurs when someone is infected with more than one strain that is then combined into a new variant. In the case of XE, according to Van Kerkhove, it is a combination of the original omicron BA.1 strain and the newer BA.2.
“We haven’t seen a change in severity,” she said, meaning it’s no more deadly than previous species.
However, the UK Department of Health report said that recent data indicates that XE may be more contagious.
But it noted that the estimate has remained inconsistent as new data is added, meaning “it cannot yet be interpreted as an estimate of the growth benefit for the recombinant.”
The earliest confirmed case of XE has a specimen date of January 19 and has been detected in the UK, Thailand, India, Israel and most recently Japan. The US has not yet reported a case of the subvariant.
According to the latest data from the UK Health Security Agency, the number of cases of the new species has nearly doubled in Britain. About 1,125 cases of XE were identified as of April 5, up from 637 cases on March 25.
CNBCs Spencer Kimball and Karen Gilchrist contributed to this report.