Omicron subvariants XE and XM are detected in S. Korea

Omicron subvariants XE and XM were found in South Korea for the first time, following the case of the XL subvariant.

The Central Disaster and Safety Countermeasures Headquarters announced on Tuesday that two XE cases and one XM case were detected and an epidemiological investigation is being carried out. XE and XM are the mutations recombining the existing Omicron variant and the so-called ‘stealth Omicron’ variant.

One of the two XE cases in South Korea originated from the U.K., with the patient testing positive on March 27. The other XE patient tested positive in South Korea on March 30. The XM infection was detected on March 27. All patients had symptoms soon after their diagnosis and did not have symptoms much different from the existing virus. All of them have been released from quarantine.

“Given the circumstances of the patients who tested positive for XE and XM in the country, the subvariants are likely to have originated in South Korea and an investigation is being conducted accordingly,” said Lee Sang-won, the head of the epidemiological investigation and analysis team of the Central Disaster and Safety Countermeasures Headquarters.

　

The XE subvariant has 10 percent faster infection speed than the stealth Omicron. According to the World Health Organization, 489 XE cases have been identified in four countries, including the U.K., the U.S., and Ireland, since January. The U.K. Health and Safety Executive said on April 8 that it had detected 1,179 cases of XE infection in the U.K. alone. Since then, more cases have been detected in Asian countries, including Taiwan, Thailand, and Japan.

“Omicron subvariants, such as XE and XM, are largely categorized as Omicron, which means they are likely to be not much different from Omicron’s characteristics,” said a member of the Korea Disease Control and Prevention Agency. “We will strengthen monitoring as analysis data on the subvariants’ infection speed and severity is insufficient.”


Keun-Hyung Yoo noel@donga.com