A new COVID hybrid first detected in the UK could be 10% more transmissible than the BA.2 sub-variant of Omicron, the World Health Organization (WHO) has said.
There have been a total of 637 cases of XE – a recombinant of Omicron BA.1 and BA.2 – in the UK so far, according to UK Health Security Agency (UKHSA).
The WHO has now warned the variant could be the most transmissible yet, adding in a report: “Early-day estimates indicate a community growth rate advantage of 10 per cent as compared to BA.2, however, this finding requires further confirmation.”
It comes a day after COVID infection levels hit a record high in the UK, with around 4.9 million people estimated to have had COVID-19 in the week ending 26 March, according to figures from the Office for National Statistics (ONS).
The UKHSA confirmed it had analysed three recombinants - XD and XF were recombinants of Delta and Omicron BA.1, while XE is a recombinant of Omicron BA.1 and BA.2.
It said 637 cases of XE had been detected since 19 January but added there was currently insufficient evidence to conclude growth advantage or other properties of the variant.
Professor Susan Hopkins, Chief Medical Advisor, UKHSA said: “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.
“As with other kinds of variant, most will 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.
“So far there is not enough evidence to draw conclusions about transmissibility, severity or vaccine effectiveness.”
In the UK, 38 cases of XF have been identified, though none have been seen since mid-February. There is currently no evidence of community transmission within the UK.
XD has not been identified in the UK to date, though 49 cases have been reported to global databases, the majority of these are in France.
Around one in every 100 people in the UK is likely to have been newly infected with COVID-19 per day during the current surge of the virus, figures suggest.
Infections are estimated to have climbed as high as 657,300 every day by 16 March, according to new modelling published by the ONS.
This is the equivalent of roughly 1% of the population.
It is also more than double the number of daily infections occurring at the end of February.
The figures suggest that by mid-March, the virus was circulating at levels higher even than those reached during the Omicron-led surge at the start of the year.