View online edition


Mu Variant of COVID: Here’s What to Know About the New Strain

Katherine Rodriguez, NJ Advance Media for

This story is being republished under a special NJ News Commons content-sharing agreement related to COVID-19 coverage. Link to story:

The Mu variant, also known as B.1.621, is a COVID-19 virus strain that was initially discovered in Colombia in January 2021, according to the World Health Organization (WHO).

The WHO declared the strain a “variant of interest” and named it Mu on Aug. 30, 2021.

Scientists say the variant is worth watching because of Mu’s prevalence in 39 countries and 49 states in the U.S.

But a lot still is unknown about the Mu variant. It was not labeled a “variant of concern,” which only would happen if reliable data shows the variant is transmissible or has worrying characteristics like the Delta variant.

Where is the Mu variant spreading?

The Mu variant has spread to 49 states and Washington D.C. The exception is Nebraska.

WHO officials said the Mu variant appeared in 39 countries, with sporadic outbreaks across Europe and South America.

Do vaccines work against the Mu variant?

Although a lot about the Mu variant is unknown right now, initial studies suggest the strain is more resistant to antibodies from the vaccines currently on the market.