WHO warns of faster-spreading Omicron variant

Thuc Linh• April 2, 2022 15:10

WHO warned on April 1 about the new variant XE, a recombinant of two sub-lines BA.1 and BA.2 of Omicron, which has the ability to spread faster than Omicron.

"The XE recombinant variant was first detected in the UK on January 19. Experts have now confirmed that more than 600 gene sequences contain this variant," quoted from the World Health Organization (WHO) report.

According to WHO's initial estimates, the rate of community infections after the appearance of XE is 10% higher than BA.2. Thus, the variant is able to spread 43% faster than the original Omicron version. However, WHO notes that more new research is needed to confirm this.

The XE variant recombined (hybrid) from BA.1 and BA.2, according to the UK Health Security Agency (UKHSA). The agency has confirmed at least 637 cases of XE in the UK. The patients are mostly concentrated in London.

The XE transmission rate in the UK is currently below 1%. The initial growth rate of the variant is not much different from BA.2. However, as of March 16, XE is 9.8% more contagious than BA.2, a figure similar to the WHO report.

Hình ảnh đồ họa của một mẫu nCoV dưới kính hiển vi. Ảnh: NIAID — Graphic image of a nCoV sample under a microscope. Photo: NIAID
The UKHSA said the number of XE cases is too small to analyse specifically by region. BA.2 is currently the dominant variant among the Omicron sub-lineages. However, experts believe that the number of XE cases will increase in the coming time, as the hybrid variant is more transmissible.

According to the WHO, studying the variant has been challenging recently, as the number of Covid-19 infections in countries has decreased uniformly. Data is less comprehensive due to lack of testing. The ability to track where the virus is, how it is spreading and evolving is increasingly difficult.

The UK currently has three hybrid variants that need to be monitored: XD, XE and XF. Of these, XD and XP are recombinants from Delta and BA.1. Scientists have tentatively called these variants Deltacron. XF accounts for only a small fraction of UK infections and has not appeared since February 15.

The news of a hybrid strain between Delta and Omicron may sound alarming, but some researchers say there is no need to panic. “This is not a new concern,” said Dr. Etienne Simon-Loriere, a virologist at the Pasteur Institute in Paris, who led the team that isolated the Deltacron strain.

Virus recombination occurs when a person is infected with two variants at the same time. For example, a sick person goes to a crowded place, infected by many F0. Two types of variants enter the same cell. When the cell produces new viruses, their genetic material is mixed, with a high possibility of creating a hybrid variant.

The phenomenon of nCoV recombination is not new. However, most of the time, this process often leads to a dead end, the virus self-destructs because the variant with mixed genes does not function as well as the previous versions.