Omicron hybrid XE may be most transmissible COVID mutant: Researchers

The World Health Organisation (WHO) has said that the new COVID mutant strain XE (hybrid of two Omicron subvariants) is at least 10% more transmissible as compared to BA.2, which is dominant in the US.

Research is still underway to prove the high transmissibility of XE, but if proven right then it could well become the most transmissible COVID-19 mutant yet.

Susan Hopkins, chief medical adviser of Britain’s Health Security Agency (HSA), said so far there’s not enough evidence to draw conclusions about the transmissibility, severity or the effectiveness of COVID-19 vaccines against XE.

At present, three hybrid variants are in circulation — XD, XE and XF. The strains XD and XE are combination of Delta and Omicron while XF is the hybrid strain of 2 Omicron subvariants, a UK Health Security Agency (UKHSA) study has revealed.

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The BA.2 sub-variant of Omicron is the fastest spreading virus at present with most cases found in the US. Currently, the XE variant accounts for a small fraction of cases across the globe.

As per the WHO, the XE recombinant (BA.1-BA.2) was first detected in the UK on January 19 and less than 600 sequences have been reported and confirmed since. “Early-day estimates indicate a community growth rate advantage of ~10% as compared to BA.2, however this finding requires further confirmation,” the WHO stated.

The WHO is closely monitoring and assessing the public health risk related with recombinant variants like the XE, and will provide updates as further evidence becomes available.