New omicron XE variant discovered in Japan as cases in the UK increase

As of 5 April 2022, 1,125 cases of XE – a new scombinant subvariant – have been identified in the UK, up from 637 on 25 March.

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Japan has reported its first case of omicron XE – a new Covid-19 strain first discovered in the UK – as well as UK cases of subvariant increase.

The XE variant was found in a woman in her 30s who arrived at Narita International Airport from the United States on March 26th. The woman, whose nationality was not immediately revealed, was asymptomatic, Japan’s health ministry said Monday.

This comes as cases of the new strain have almost doubled in the UK, according to the latest statistics from the UK Health Safety Agency.

Pr. By 5 April, 1,125 cases of XE had been identified in the UK, up from 637 on 25 March. The earliest confirmed case has a trial date of January 19 this year, suggesting it could have been circulating in the population for several months.

XE has since been discovered in Thailand, India and Israel. It is suspected that the latter Israeli cases may have developed independently. The United States has not yet reported any XE cases.

What is omicron XE?

XE is what is known as a “recombinant”, a type of variant that can occur when an individual becomes infected with two or more variants at the same time, resulting in a mixture of their genetic material in a patient’s body.

In the case of XE, it contains a mixture of the previously highly infectious omicron BA.1 strain, which appeared in late 2021, and the newer “stealth” BA.2 variant, which is currently the UK’s dominant variant.

Such recombinants are not uncommon as they have occurred several times during coronavirus pandemic. However, health experts say it is too early to draw conclusions about the severity or ability of the new subvariant to avoid vaccines.

“We continue to monitor cases of the recombinant XE variant in the UK, which currently represents a very small proportion of cases,” said Meera Chand, Director of Clinical and New Infections at UKHSA, in a statement.

On Sunday, the UK reported 41,469 new Covid cases with a seven-day average of 59,578 cases. As such, XE probably accounts for only a small percentage of total Covid cases at present.

How worried should we be?

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XE contains peak and structural proteins from the same virus family, i.e. omicron, which means that it should at least theoretically behave as omicron has done before. Existing vaccines and immunity should therefore provide some degree of protection against infection.

“Recombinants that contain the tip and structural proteins of a single virus (such as XE or XF) are likely to act in the same way as [their] parental virus, “wrote Tom Peacock, virologist at Imperial College London’s Department of Infectious Disease, in a thread of tweets in mid-March. XF refers to another recombinant previously detected in the UK in February.

However, other recombinants containing spike and structural proteins from different virus families continue to emerge. It includes the XD sub-variant, which was recently discovered in Germany, the Netherlands and Denmark, and which contains delta-structural proteins and omicron spike proteins, and which Peacock described as “a little more worrying.”

As such, all new incidents need to be closely monitored, especially in their early stages, to ensure that they do not develop into something more serious.

“The virus is still able to evolve, recombine and develop a new branch of its pedigree,” Cameron said.

The most important thing is that for each of these variants and sub-variants, the risk of hospitalization and death appears to be lower on average, with vaccination rates being higher, indicating that vaccination, including a third dose, should be effective in reducing the risk. for serious illness, “added Stephanie Silvera, a professor of public health at Montclair State University.

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