COVID-19's mu variant: What you need to know

New 'MU' COVID-19 variant on the rise

Doctor Mike joins Good Day Philadelphia to discuss some of the latest COVID news.

PHILADELPHIA - The World Health Organization has identified the COVID-19 mu strain as a "variant of interest." Health officials are keeping an eye on the new strain to see if it becomes dominant.

WHO defines variants of interest as COVID-19 strains that have the potential to affect the virus' transmissibility and disease severity. They could also be responsible for outbreaks in multiple countries over time.

"The Mu variant has a constellation of mutations that indicate potential properties of immune escape. Preliminary data presented to the Virus Evolution Working Group show a reduction in neutralization capacity of convalescent and vaccinee sera similar to that seen for the Beta variant, but this needs to be confirmed by further studies," WHO wrote in their weekly bulletin.

Dr. Anthony Fauci, the government’s leading infectious disease expert, said Sunday the mu variant was "not an immediate threat." He added that the delta variant represented over 99% of the cases.

Where was the mu strain first identified?

The strain, also known as B.1.621, was first identified in Colombia in Jan. 2021 but didn't receive an official destination until Aug. 30.

How fast is it spreading?

So far, 49 U.S. states and the District of Columbia have since detected the mu variant, with the exception of Nebraska, according to estimates compiled by Outbreak.info. States with a higher estimated prevalence of the variant include Alaska and Hawaii. The variant has been detected in less than 1% of samples nationwide.

WHO officials said the mu strain has appeared in 39 countries with sporadic outbreaks in South America and Europe. The epidemiology of the mu variant in South America, particularly with the co-circulation of the delta variant, will be monitored for changes, according to WHO.

Are there cases in Pennsylvania, New Jersey and Delaware?

The mu strain accounts for a very small proportion of variant cases in New Jersey but officials continue to monitor it.

"The Mu variant accounts for a very, very small proportion of variant cases in NJ and US but we continue to monitor it. The CDC has not classified Mu as either a variant of concern or interest, as there still needs to be an evaluation of this variant as the data are somewhat limited at this time," a spokesperson for the New Jersey Department of Health said in a statement. "Regardless, the public health recommendations do not change—get vaccinated, mask, social distance, etc."

Health officials in Pennsylvania said as of Aug. 31 there have been no reported cases of the mu variant in the state.

FOX 29 reached out to the Delaware Department of Health but has not heard back at this time.