New COVID-19 Mu Variant Named a “Variant of Interest”

© Provided by New COVID Variant MuThis particular variant “has a constellation of mutations that indicate potential properties of immune escape,” according to a weekly bulletin from the WHO. But what else do researchers know about Mu, and is it more serious than the Delta variant? Here’s what we know so far.

background pattern: There's still a lot to learn about this new variant.© Provided by There’s still a lot to learn about this new variant.

What is the Mu variant, exactly?

The Mu variant was first identified in Colombia in January 2021, according to the WHO. Since that time, there have been some scattered cases, as well as reports of larger outbreaks, around the world, including in other areas of South America, the UK, Europe, the US, and Hong Kong.

As a variant of interest, Mu has “a constellation of mutations that indicate potential properties of immune escape” according to the weekly bulletin from the WHO. In addition, variants of interest are defined as those that have genetic changes that are known to (or are predicted to) affect certain virus characteristics, including disease severity, immune escape, diagnostic or therapeutic escape, and transmissibility, and have been “identified to cause significant community transmission or multiple COVID-19 clusters, in multiple countries with increasing relative prevalence alongside increasing number of cases over time, or other apparent epidemiological impacts to suggest an emerging risk to global public health,” according to the WHO. However, the organization also says more research is needed to fully understand Mu and what it’s capable of.

How worried should you be about the Mu variant?

This particular variant isn’t as widespread at the moment as many other that are listed as “of interest.” According to data from the WHO bulletin, it currently makes up less than 0.1% of COVID-19 infections in the world, though rates are higher in certain countries, including Colombia (where it accounts for 39% of cases) and Ecuador (13%).

Worth noting, however: Mu is currently not on the Centers for Disease Control and Prevention’s list of variants of interest or variants of concern, at least for the time being.

“It’s not very concerning at the present time,” William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine, tells Health. He points out that Mu was first detected in January of this year and is only now being named a variant of interest. “Researchers are still assessing how quickly it spreads and what its level of contagiousness is,” he says. “It’s interesting that it’s even reached the level of becoming a variant of interest [with the WHO].”

Infectious disease expert Amesh A. Adalja, M.D., a senior scholar at the Johns Hopkins Center for Health Security agrees that there’s no reason to panic over Mu at the moment. ” People should not be so worried about this variant,” he tells Health. “Variants are continuously being generated.”

Dr. Adalja also doesn’t think that Mu will overtake the Delta variant. “It’s unlikely that it is more fit than Delta and will be able to overtake it,” he says.

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