As the World Health Organization added the new COVID strain “mu” to its variants “of interest” list, top health officials said Thursday it does not pose an “immediate threat” to the U.S. right now. 

“We’re paying attention to it, we take everything like that seriously, but we don’t consider it an immediate threat right now,” White House chief medical advisor Dr. Anthony Fauci said at a press briefing.

Variant B.1.621, also known as mu, was added to the WHO’s watch list on Monday. It is one of the now five variants of interest added to the international health organization’s list since March 2021.

This list includes variants that are identified to cause significant "community transmission” and pose a risk of “increasing number of cases over time” that may cause varied severity and transmissibility compared to other strains.

“This variant has a constellation of mutations that suggests that it would evade certain antibodies, not only monoclonal antibodies, but vaccine- and convalescent serum-induced antibodies,” Fauci said. “But there isn’t a lot of clinical data to suggest that, it is mostly laboratory in-vitro data.”

Fauci added that though current vaccines were created using the initial COVID-19 strain, it still offers strong protection against variants of the time.

CNBC said that the Delta variant was in the WHO’s list of interest until May when it was reclassified for causing major outbreaks in the U.S.

Unlike the Delta variant, mu “isn’t even close to being dominant” in the U.S., Fauci said.

Mu was added to WHO’s watchlist after it was identified in 39 countries for having “a constellation of mutations that indicate potential properties of immune escape,” WHO said.

This new variant was first identified in Colombia. Now it makes up for less than 0.1% of Covid infections globally but it has been making a greater impact in Colombia and Ecuador, accounting for 39% and 13% of Covid cases respectively.