LA County confirms cases of potentially infectious Mu variant of COVID-19

While the highly infectious Delta variant of COVID- 19 remains the dominant strain of the virus in Los Angeles County, health officials Friday confirmed the presence of what’s known as the Mu variant, which is also described as highly contagious and potentially able to evade vaccines.

According to the county Department of Public Health, 167 Mu variants have been detected in the county, all between June 19 and Aug. 21, with most of them found in July.

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. Some initial reviews of the variant have indicated it has the potential to evade currently available vaccines. But 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.”

The Delta variant remains the dominant COVID-19 strain circulating in the county, with Public Health Director Barbara Ferrer saying  it represents nearly all of the cases that undergo the sequencing needed to identify specific viral mutations. Delta is 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 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. “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%.

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