What To Know About The Mu Variant Detected In Los Angeles

LOS ANGELES, CA — The highly contagious Mu variant of the coronavirus has been detected in Los Angeles County, health officials confirmed Friday. According to the World Health Organization, the Mu variant contains genetic variants that could make it somewhat resistant to natural immunity, current vaccines and monoclonal antibody treatments.

"The Mu variant has a constellation of mutations that indicate potential properties of immune escape," the WHO reported. "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."

According to the county Department of Public Health, the Mu variant was detected in the county as early as June 19. There have been 167 confirmed cases of the Mu variant through Aug. 21.

In a statement Friday, county health officials said "more studies are needed to determine whether Mu variant is more contagious, more deadly or more resistant to vaccine and treatments than other COVID-19 strains."

At a press briefing Thursday, the nation's top infectious-disease expert Anthony Fauci said scientists are watching the variant closely, but it's not currently an 'immediate threat.' Delta remains the biggest threat facing the nation.

“Certain features in coronavirus variants appear to make the virus more infectious and we are seeing some of those features in the mu variant,” Stuart Ray, a professor of medicine at John Hopkins University told USA Today. “But right now, we don’t have any huge concerns.”

He said the variant is unlikely to surpass the delta variant cases in the United States.

The Mu variant -- officially labeled a "variant of interest" by the World Health Organization -- was first discovered in Colombia in January, and it has since been detected in 39 countries.

For now, the highly infectious Delta variant of COVID- 19 remains the dominant strain of the virus in Los Angeles County. According to Public Health Director Barbara Ferrer, the Delta variant represents nearly all of the cases that undergo the sequencing needed to identify specific viral mutations. Delta is also labeled a "variant of concern" by the WHO.

"The identification of variants like Mu, and the spreading of variants across the globe, highlights the need for L.A. County residents to continue to take measures to protect themselves and others," Ferrer said in a statement Friday. "This is what makes getting vaccinated and layering protections so important. These are actions that break the chain of transmission and limits COVID-19 proliferation that allows for the virus to mutate into something that could be more dangerous."

The county reported another 37 COVID-19 deaths on Friday, raising the cumulative death toll from the virus to 25,401. Another 2,673 cases were also confirmed, lifting the overall total from throughout the pandemic to 1,414,854.

The number of COVID-positive hospital patients in the county continued a steady decline, with state figures putting the figure at 1,593 as of Friday, down from 1,641 on Thursday. There were 453 patients in intensive care, up from 445 a day earlier.

Ferrer noted Thursday that the county has begun to see decreases in the rate of new infections. According to Ferrer, the county's cumulative seven-day rate of new cases was 159 per 100,000 residents this week, a 16% drop from last week and down 22% from the peak of 204 per 100,000 residents in mid- August.

"It's important to note we are seeing less transmission across the board in general, but because the Delta variant is so capable of infecting lots of people, we still have very high numbers of people getting infected," Ferrer said Thursday. "And while in L.A. County, you look at our numbers and say we have tons and tons of people vaccinated ... but we also have tons and tons of people that are unvaccinated -- a very good reservoir for highly infectious variants."

The county's rate of people testing positive for the virus rose Friday to 3.3%, up from 2.97% a day earlier.

Among eligible county residents aged 12 and over, 75% have received at least one dose of vaccine, while 65% are fully vaccinated.

Again touting the effectiveness of the vaccines, Ferrer said that of nearly 5.3 million residents who were fully vaccinated as of Tuesday, 37,614 have tested positive for the virus, for a rate of 0.71%, while 1,049 have been hospitalized, a rate of 0.02%. Of those fully vaccinated, 118 have died, for a rate of 0.0022%.

City News Service and Patch Staffer Paige Austin contributed to this report.