The new hybrid COVID-19 variant might be the fastest-spreading strain yet, according to preliminary research, but studies are underway to determine the exact contagiousness of the variant.

XE was first detected in mid-January in the United Kingdom, where more than 600 cases have been reported since then, according to the UK’s Health Security Agency.

The XE variant is a recombinant, comprised of genetic material from two other strains, which in this case are BA.1, the original strain of Omicron, and BA.2, known as “stealth Omicron”.

Early growth rates of the variant weren’t significantly different from BA.2, the UK Health Security Agency initially said.

In an update on March 25, health authorities then revealed more recent data showed XE had a growth rate of 9.8 per cent above BA.2.

The World Health Organisation released similar information, citing estimates that show XE is 10 per cent more transmissible than BA.2.

However, those findings require further confirmation, the agency noted.

BA.2 was previously identified as the most transmissible variant, as it spreads about 75 per cent faster than BA.1, according to health officials.

The recombination is showing signs of higher transmissibility, but it is not expected to cause more severe COVID-19 or dodge vaccines more than the original variant

Along with the XE variant, UK’s Health Security Agency is monitoring two other recombinants: XD and XF, which consist of genetic material from the Delta and BA.1 strains.

UK health authorities previously said there was “insufficient evidence to draw conclusions about growth advantage or other properties of this variant,” but addressed initial reports about its infectiousness.

“This particular recombinant, XE, has shown a variable growth rate, and we cannot yet confirm whether it has a true growth advantage,” stated Susan Hopkins, chief medical adviser for UKHSA.

Recombinant variants themselves, however, are not out of the ordinary, according to health officials.

“Recombinant variants are not an unusual occurrence, particularly when there are several variants in circulation, and several have been identified over the course of the pandemic to date,” Hopkins said.

“As with other kinds of variant, most will die off relatively quickly.”

WHO said it would continue to study recombinants and provide updates as further evidence becomes available.