April 6 (UPI) -- Researchers are beginning to learn more about yet another COVID-19 strain -- this one a subvariant of two different types of the more infectious Omicron strain that has been found in hundreds of cases in Britain.
Scientists say that the new mutation -- Omicron XE -- is effectively a mix of the BA.1 and BA.2 Omicron variants that emerged in 2021. Omicron XE is a recombinant, which is a variant that occurs when someone is infected with multiple variants at the same time.
The newer BA.2 "stealth" Omicron variant has been the dominant strain in Britain for months.
British health officials say Omicron XE has been found in more than 600 cases so far -- but the scientific community is not sure yet how infectious the new subvariant is or whether it's more or less dangerous than previous mutations. Experts also don't know yet how effective the available vaccines are against the new mutation.
The World Health Organization said in a report last week that Omicron XE is estimated to be 10% more transmissible than BA.2, but acknowledged that data so far is limited.
"XE has shown a variable growth rate and we cannot yet confirm whether it has a true growth advantage," British medical adviser Susan Hopkins said in a statement. "So far there is not enough evidence to draw conclusions about transmissibility, severity or vaccine effectiveness."
British health officials have said they are also monitoring two other COVID-19 recombinants -- XD and XF. Both are combinations of the Delta and Omicron BA.1 strains.
Omicron XE is worrying some officials that it may lead to another surge in hospitalizations in Britain. According to government health figures, more than 20,000 Britons were in hospitals with COVID-19 by early this week.
Some health experts told Newsweek, however, that it's unlikely that the new recombinants will become a major concern.
"I find it very disappointing and unhelpful how much people are hyping these variants," Jeremy Kamil, associate professor of microbiology and immunology at Louisiana State University Health Shreveport, said. "They are scientifically interesting but remain largely a curiosity.
"These are not at all likely to pose a special or unique threat and we should not treat them as if they do."
"It is too early to assess the full significance," added Andrew Freedman, a reader in infectious diseases at Cardiff University's Center for Medical Education. "But I would not be unduly concerned at this stage.
"I think of much greater concern would be the appearance in the future of a new variant that might be even more transmissible than Omicron and more virulent, as well as being able to evade the immunity conferred by the current vaccines and previous infections."
