A new coronavirus variant known as “Mu” has been monitored, the World Health Organization (WHO) said on Tuesday.

“Mu”, known scientifically as B.1.621, was classified by WHO as a “variant of interest” on Monday.

“The Mu variant has a constellation of mutations that indicate potential properties of immune escape,” WHO said in its weekly COVID-19 update.

It said the new variant, which was first detected in Colombia last January, is similar to the Beta variant in that shows a “reduction in neutralization capacity of convalescent and vaccinee sera.”

There “Mu” variant has had large outbreaks in South America and Europe.

“Although the global prevalence of the Mu variant among sequenced cases has declined and is currently below 0.1 percent, the prevalence in Colombia (39 percent) and Ecuador (13 percent) has consistently increased,” WHO said.

WHO said there’s a need for further studies to understand the clinical characteristics of this strain.

Variants of the coronavirus have raised concerns among health experts the world over. With the highly transmissible Delta variant and its capability of causing infection among some inoculating people dominating headlines.

Currently, there are 193 countries where the Alpha variant exists, 141 countries where Beta exists, 91 countries where Gamma exists, and 170 countries where Delta exists, according to WHO data.