The United Kingdom has recently detected a new subvariant of the mutant Omicron strain, called the XE variant, and a few cases have been identified elsewhere in the world.

As of April 5, 1,125 cases of XE have been identified in the U.K, almost double from the 637 recorded on March 25, according to the latest statistics from the U.K. Health Security Agency (UKHSA).

What do we know about the XE variant?

XE is known as a recombinant virus, which occurs when an individual becomes infected with two or more variants at the same time--in this case the original Omicron strain (BA.1) and a highly circulating subvariant of Omicron (BA.2)--resulting in a new subvariant from the mixing of their genetic material within a patient's body, according to the agency. UKHSA has identified three mutations that aren't present in the BA.1 or BA.2 strains.

"Recombinant variants are not an unusual occurrence, particularly when there are servea; variant in circulation, and several have been identified over the course of the pandemic to date," said Susan Hopkins, chief medical advisor of UKHSA, in a press statement.

Is is more transmissible than Omicron?

Hopkins noted that XE has shown a "variable growth rate" and scientists cannot yet confirmed whether its has a "true growth advantage," over other variants. UKHSA data shows XE has a growth rate of 9.8% above that of BA.2, which is the dominant variant in the U.K, CNBC reports. The World Health Organization has estimated that XE's growth rate is high as 10%.

"So far there is not enough evidence to draw conclusions about transmissibility, severity or vaccine effectiveness," Hopkins added. "As with other kinds of variant[s], most will die off relatively quickly."

The earliest confirmed case of XE in the U.K. was tested on Jan. 19 of this year, CNBC reports, meaning that the mutant subvariant may have been circulating in the country for several months. Cases of XE have been detected in other nations including Thailand, India, Japan and Israel. The United States has not reported any XE cases at date.

Will vaccines remain effective?

Like all new strains of the original SARS-COV-2 virus, scientists and public health experts are concerned that current vaccines may not be as effective against XE. However, like the Omicron strain, it's possible that current vaccines may provide enough protection against severe infections, hospitalization and death due to the strain's genetic makeup.

"We know the vaccines work to protect against symptomatic disease for BA.1 and BA.2, and therefore we have every reason to suspect that vaccination strategies will have activity to protect against symptomatic disease caused by XE," Dr. Andrew Badley, chair of the SARS-CoV-2 COVID-19 Task Force at Mayo Clinic, told Time Magazine.