India recorded the first case of the more transmissible Covid-19 variant ‘XE’ in Mumbai on Wednesday. A case of the Kappa variant was also detected during a sero survey. On the other hand, Shanghai recorded over 17000 cases in a day, as the district authorities started a second round of mass testing.
The new Covid variant XE is more transmissible than any other Covid strain so far, says World Health Organisation (WHO). The UN health agency had earlier this week flagged the emergence of the new coronavirus variant XE– a hybrid of the BA.1 and BA.2 variations of Omicron.
The XE variant was first detected in UK in January, the global health agency said in its weekly epidemiological update. The UK Health Security Agency (UKHSCA) has also been studying the recombinant variant.
What is XE variant?
XE is combination or recombinant of both sub-variants (BA.1 and BA.2) of Omicron. The recombinant variant appears to be, as per the WHO, 10% more transmissible than the BA.2 sub-variant of Omicron. “Early-day estimates indicate a community growth rate advantage of 10 percent as compared to BA.2, however, this finding requires further confirmation,” says the WHO.
A UK Health Security Agency (UKHSA) study recently revealed that currently as many are 3 hybrid COVID variants are circulating. The two different combinations of Delta and BA.1 are XD and XF. The third is XE.
WHO’s warning on XE:-
The WHO on 1 April issued a report on its findings about XE. “The XE recombinant was first detected in the United Kingdom on 19 January and >600 sequences have been reported and confirmed since,” the WHO research shows. Earlier, the UN health agency had issued warnings against Omicron, Delta recombinant virus, saying with both Omicron and Delta circulating in a massive scale, this was highly expected.
“This particular recombinant, XE, has shown a variable growth rate and we cannot yet confirm whether it has a true growth advantage,” the agency’s chief medical advisor Susan Hopkins said. “So far there is not enough evidence to draw conclusions about transmissibility, severity or vaccine effectiveness.”
Is it worrisome?
As per eminent virologist Tom Peacock, recombinants that contain the spike and structural proteins from a single virus (like XE or XF) are fairly likely to act similarly to their parental virus.
Experts say XD is maybe a little more concerning than XE. It has been found in Germany, Netherlands and Denmark. It contains the structural proteins from Delta – if any of these recombinants were to act much differently than its parent it might be XD.
UKHSCA has pointed out on 16 March that this XE variant now has a growth rate 9.8% above that of the BA.2 stealth variant.
The body cautioned though that “as this estimate has not remained consistent as new data have been added, it cannot yet be interpreted as an estimate of growth advantage for the recombinant.”
“Numbers were too small for the XE recombinant to be analysed by region,” the UKHSCA said.
Professor Susan Hopkins, the UKHSA’s chief medical advisor transition lead, said that recombinant variants are not uncommon and usually die off “relatively quickly”.
“This particular recombinant, XE, has shown a variable growth rate and we cannot yet confirm whether it has a true growth advantage,” Ms Hopkins told The Sun.
“So far there is not enough evidence to draw conclusions about transmissibility, severity or vaccine effectiveness.”
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