Health officials are tracking a new Omicron subvariant, classified as XE, which is a hybrid of two previously identified subvariants. This type of “recombinant” sub-lineage contains genetic material from two or more different viruses and is not new, but this particular one has attracted some attention due to evidence of community transmission.
Since South African scientists first identified Omicron more than four months ago, several subtypes have evolved, including Ba.2 which is currently circulating in Canada and elsewhere around the world. Here’s what we know so far about the XE subvariant:
What is XE sub-lineage?
XE is a recombinant of BA.1, which powered the Canadian fifth wave during the winter holidays and throughout January, and BA.2, which is fueling the current sixth wave. According to a technical briefing released by the UK Health Protection Agency (UKHSA) on 8 April, as of 5 April there were 1,125 cases of XE in England, which was less than one per cent of the total sequences.
In addition to mutations from BA.1 and BA.2, as reported by UK, XE also contains three mutations that are not present in all sequences of BA.1 and BA.2.
How common are recombinant types?
“Recombinant variants are not an uncommon occurrence, especially when there are multiple variants in circulation,” Dr. Susan Hopkins, UKHSA’s chief medical adviser, said in a statement on March 25.
“Many have been identified during the pandemic till date. As with the other type types, most will die relatively quickly.”
UK previously identified other recombinants including XD and XF, which are recombinants of Delta and Omicron BA.1.
How permeable is it?
The World Health Organization’s technical lead, Dr. Maria Van Kerkhove, said in a video question-and-answer brief that based on a preliminary analysis of the available sequences, there is an increase in transmissibility in Xe by about 10 percent. However, Van Kerkhove said that reports that it is 10 times more permeable are incorrect.
The UK health agency said there was an average growth rate of 12.6 per cent per week above BA.2, but noted that the growth rate increased to 20.9 per cent over the past three weeks.
The WHO classifies XE under Omicron, a type of concern. The agency said that the subtypes and recombinant forms as separate lineages should be monitored by public health officials.
The Public Health Agency of Canada (PHAC) says it is actively monitoring COVID-19 variants, and is evaluating new Omciron sub-lineages and recombinants, such as XE.
In an email on Thursday, CTVNews.ca spokesman Mark Johnson told CTVNews.ca: “Scientists are looking for signs that XE alters the severity of the disease, or that clinical trials for COVID-19 are being conducted. , affects the effectiveness of vaccines or treatments.”
“While preliminary international reports showed that XE increased marginally compared to BA.2, more data are needed to confirm this finding.”
Where have XE cases been identified?
According to PHAC, as of April 14, one case of the XE sub-lineage collected from border surveillance on March 22, 2022 has been confirmed in Canada.
“PHAC had previously suspected five possible detections in addition to XE; however, upon further investigation, it was determined that they were not XEs, but of an undetermined lineage, which is undergoing refinement,” Johnson he said.
“It should be noted that currently several recombinants of COVID-19 other than XE are being tracked globally, which suggests the overlap of Delta and Omicron variants as well as co-circulation of BA.1 and BA. Not surprising given that. .2 Sub-lineage of Omicron.
In the UK, the majority of cases are concentrated in the East of England, London and the South East, according to the UK Health Agency report, with the first case reported on 19 January.
According to various media reports, XE cases have also been detected in India, Japan and other countries.
Do Vaccines Still Work?
While scientists are still learning more about Xe and other sub-lineages, research and real-world data suggest that vaccines provide protection against serious disease, especially after a booster shot.
“We need to make sure you get vaccinated when it’s your turn and you get the full course of doses,” WHO’s Van Kerkhove said. staff.