SALT LAKE CITY (ABC4) – The World Health Organization is recognizing a new COVID-19 variant, calling it a ‘Variant of Interest.’ With this addition of the ‘Mu’ variant, WHO is now monitoring five variants of interest worldwide.

While the Delta variant remains the most prevalent in the U.S. and Utah – where over 6,500 have been confirmed since April – health officials recently expressed concerns about two variants, the Lambda strain and B.1.621.

The B.1.621 variant was discovered in Colombia earlier this year and has been reported in Utah. Just a week ago, WHO had not yet given the variant a name, despite it causing an outbreak in a Belgium nursing home and killing seven fully-vaccinated people. Additionally, ABC4 affiliate WFLA reports the variant has spread in the Jacksonville area.

In its weekly COVID-19 epidemiological update released Tuesday, WHO reports that following the latest round of assessments, the B.1.621 variant has been classified as a Variant of Interest and given the label ‘Mu.’ According to WHO, since being detected in January, this variant has been responsible for “a few sporadic reports of cases” and “some larger outbreaks have been reported from other countries in South America and in Europe.”

As of August 29, WHO reports over 4,500 sequences of the Mu variant have been reported by 39 countries. WHO says that while cases of Mu have declined, the prevalence in Colombia and Ecuador has consistently increased.

Dr. Kelly Oakeson, Chief Scientist with Next-Generation Sequencing & Bioinformatics, tells the Mu lineage was first detected in Utah in May. Since then, Dr. Oakeson reports a total of about 300 cases of the variant have been sequenced. The B.1.621 ‘Mu’ variant does not appear more lethal than the Delta variant, health experts say, and “very few patients” have been seen at a Tampa hospital with either.

The CDC reports this variant makes up about 0.2% of the COVID-19 cases in the U.S. between Aug. 22 and 28. Because the Mu variant has not been declared a Variant of Concern by WHO, the Utah Department of Health is not reporting cases sequenced on its dashbord. For now, the Mu variant remains on WHO’s list of Variants of Interest, meaning it has been “identified to cause significant community transmission or multiple COVID-19 clusters.”