Omicron sub variants BA.4 and BA.5 circulate at low levels in several countries within Southern Africa and Europe, according to the World Health Organization.
The two variants of the highly contagious Covid-19 strain have been detected in Botswana, South Africa, Germany and Denmark, among other countries, WHO technical lead on Covid-19 Maria Van Kerkhove said Thursday.
She added that BA.4 and BA.5 do not appear to be more contagious or fatal than the original omicron mutation yet, but that this could change as more cases are discovered. Van Kerkhove emphasized the need to maintain “robust” genome surveillance systems that would allow countries to track and analyze the two sub-variables as well as previous versions of omicron.
“It’s still early days,” Van Kerkhove said during the WHO briefing. “What we have to make sure is that we still have the ability to trace, the ability to share, the ability to analyze so that we can answer questions like this.” It was broadcast live on the organization’s social media platforms.
Her comments come days after the World Health Organization said it was tracking a few dozen cases of BA.4 and BA.5, as well as previous omicron variants such as BA.1, BA.2, BA.3 and BA.1.1.
A new wave of issues
It also comes as the more contagious BA.2 variant has advanced across several parts of the world, leading to a new wave of Covid cases following the unprecedented spike caused by the original omicron variant, BA.1, during the winter. The BA.2 strain is the world’s dominant strain. In the United States, it makes up about 85% of new serial cases and is most prevalent in the northeastern region of the country where it accounts for about 92% of newly serialized cases, according to data from the Centers for Disease Control and Prevention.
The earliest BA.4 sample was collected in South Africa on 3 January. 10, but the data show that the ‘genome accumulation’ and geographic spread of the sub-variant is recent, according to a report from the UK’s Health Security Agency released last week. As of April 8, South Africa has reported 41 cases of BA.4, Denmark has reported three, Botswana has reported two, and England and Scotland have reported one each.
“Although the total number of genomes is small, the clear geographic spread indicates that the variant is successfully transmitted,” the Department of Health said in a report.
The report also stated that there were 27 reported sequences for BA.5 as of 8 April, all reported in South Africa between 4 February. From 25 to 25 March. But Botswana’s Ministry of Health said on Monday it had identified both BA.4 and BA.5 among fully vaccinated individuals between the ages of 30 and 50, Reuters reported.
The World Health Organization began tracking BA.4 and BA.5 because they both have new mutations that “need further study to understand their impact on immune escape potential,” according to Reuters.
Both variants contain additional mutations in the region of the spike, a 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 linked to “potential immune escape properties,” the report said.
XE variant
Other omicron scientists call XE also traded at low levels in a number of countries.
XE is a “recombinant” variant that occurs when a person is infected with more than one strain that later combine to form a new variant. In the case of XE, it’s a mixture of the original omicron BA.1 strain and the newer BA.2 strain, according to Van Kerkhove.
“We did not see a change in severity,” she said, meaning that it is no more lethal than previous strains.
However, the report from the UK Department of Health stated that recent data suggests that XE may be more contagious.
But she noted that the estimate did not remain consistent with the addition of new data, which means that it “cannot yet be interpreted as an estimate of the growth advantage for the recombinant.”
The first confirmed case of XE has a typical date of January 3. 19, and it was discovered in the UK, Thailand, India, Israel and most recently Japan. The United States has not yet reported the status of the dependent component.
Cases of the new strain in Britain have nearly doubled, according to the latest data from the UK’s Health Security Agency. About 1,125 cases of XE were identified as of April 5, up from 637 on March 25.
CNBC Spencer Kimball And Karen Gilchrist Contribute to this report.