Data from UK
XE, XF, XD – what you should know about the new recombination of the corona virus
It is not unusual for new variants of the corona virus to form. In Great Britain, researchers have observed the Omikron XE recombination more closely.
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Various corona variants are currently circulating around the world. In the UK, researchers are observing three new recombination events. One of them could be more contagious than previous variants.
Although the newly reported corona cases in Germany are declining, they are still at a high level. If the first omicron wave in the Federal Republic was triggered by subvariant BA.1, almost 90 percent of new infections are currently due to subvariant BA.2, as the current weekly report from the Robert Koch Institute shows.
Researchers from Great Britain are now drawing attention to three new virus variants. These are mixed variants, called recombinations, from omicron subtypes or delta and an omicron subvariant. The most recent report by the British UK Health Security Agency (UKHSA) focuses on the omicron recombination XE. How dangerous are the new virus variants and what is known about them so far?
XE is a recombination of the omicron subtypes BA.1 and BA.2. She also has three new mutations. This variant was first detected on January 19, 2022 in Great Britain. In the UKHSA report, 637 cases of XE were detected in England up to 22 March 2022, with a total of 763 recombination cases recorded. They found researchers mainly in London, in the south-east of England and in the east of England. So far, Omikron XE accounts for only a marginal part of the infections, not even one percent of the corona infections in the reporting period.
However, the data from Great Britain provide the first indications that Omikron XE could spread even faster than the previous variants: While the initially calculated growth rate of Omikron XE was not significantly different from BA.2, the rate was now significantly higher. The new variant outperformed BA.2 by 9.8 per cent, according to the UKHSA report. The researchers used data from March 16, 2022. The World Health Organization (WHO) also assumes that XE is 10 percent more contagious than subvariant BA.2.
Recombination XE – more data needed
“Recombinant Omicron XE has a variable growth rate, but we cannot yet confirm if it has a real growth advantage. There is still too little evidence to draw any conclusions about the transmissibility, severity or efficacy of the vaccine,” says Susan Hopkins, Senior Medical Advisor to the UKHSA. The British health authority will continue to closely monitor the Sars-CoV-2 variants. So far, the WHO continues to monitor the new recombination under the omicron and does not yet consider it a worrying variant. This will not change until “significant differences in transmission and disease characteristics are reported”.
The WHO still classifies the risk of new variants including recombinations as high. Such recombination can occur when a person is infected with two or more variants at the same time. Mixing of the genetic material of the coronaviruses occurs in the body of the infected person. “Recombinations are not uncommon, especially when multiple variants are in circulation, and several have been identified so far during the pandemic,” explains Susan Hopkins. However, most recombination cannot prevail against the prevailing variants of the coronavirus and so most variants die relatively quickly.
Few cases of XD and XF so far
In addition to Omicron XE, the British Health Authority mentions two other recombination in their report – XD and XF. Both are combinations of genetic material from the omicron subvariant BA.1 and Delta. XD has not yet been detected in the UK (report as of March 22, 2022). 49 cases have been documented worldwide, most of them in France, but recombination has also appeared in Denmark and Belgium.
The variant is being monitored by the WHO despite the very limited spread. So far there is no evidence that XD is more easily transmissible than other circulating variants, the WHO writes in its weekly report. 39 cases of Omicron XF have been identified in the UK, but there have been no new cases since mid-February.
Sources:UKHSA report, RKI weekly report, Weekly Report WHO April, Weekly report WHO March, UK Gov