Although Florida is finally starting to see a decrease in the number of new COVID-19 cases, there have been hundreds of cases detected of the Mu variant, which is more transmissible and potentially more resistant to vaccines than other strains.
Florida is getting over its worst wave of the pandemic, where as many as 27,779 new COVID-19 cases were recorded in the Sunshine State in one day. On September 6 it recorded 10,162 new cases. Some 305 of its active cases are the Mu variant, according to data from the Outbreak.info website.
However, the Delta variant remains by far the dominant strain and Mu only accounts for 0.2 percent of the total cases in the U.S.
Dr. Jason Salemi, an epidemiologist with the University of South Florida, told Newsweek: "I am absolutely concerned about Mu. It's likely now in well over 40 countries, cases of this variants have appeared all over the U.S., and it possesses mutations that suggest it has the potential to effectively combat what our immune systems are throwing at it."
"If, in fact, the variant is capable of substantially reducing the effectiveness of vaccines in lowering the risk of severe illness...well, it's one of those situations that we've been worried about."
He said if the world fails to achieve "meaningful vaccination coverage" it is more likely that variants such as Mu will emerge.
"This is the battle—we're doing everything we can to stamp out the deleterious effects of the virus, and it's fighting back, primarily with mutations that can make it spread more easily, cause more severe illness, and/or evade our defenses."
Salemi said that there is still much to learn about Mu and its capabilities.
"With Delta comprising 99 percent of all [U.S.] cases, we need to continue to focus on measures to combat the current wave, that despite showing declines (in cases, hospitalizations) in recent weeks, has been the most deadly wave of the pandemic in my home state of Florida."
He said that variants like Mu should underscore the importance of getting people vaccinated to minimize the likelihood of new, more resistant variants emerging and running amok.
The WHO and the Centers for Disease Control and Prevention (CDC) have three categories of COVID variants that make up their watch lists: variants of interest (VOI), variants of concern—which includes Alpha, Beta, Delta and Gamma—and variants of high consequence.
The WHO officially labeled the Mu variant a VOI on August 30, meaning the variant has genetic differences to the other known variants and is causing infections in multiple countries, meaning it might present a particular threat to public health. However, the numbers globally are low at present, meaning it is not a variant of concern.
In its weekly epidemiological update published on September 1, the WHO wrote: "The Mu variant has a constellation of mutations that indicate potential properties of immune escape."
The WHO noted that vaccinated individuals appear to show a "reduction in neutralization capacity" against Mu and may have "potential properties" that are synonymous with the Beta variant.
Mu was first detected in Colombia in January. It has since been found in at least 40 countries but is thought to currently be responsible for only 0.1 percent of global infections. The variant has been found in every U.S. state apart from Nebraska.
On Sunday, Dr. Anthony Fauci said that although Mu wasn't an "immediate threat," scientists will be "keeping a very close eye on it."
"This variant has a constellation of mutations that suggests that it would evade certain antibodies, not only monoclonal antibodies, but vaccine- and convalescent serum-induced antibodies," Fauci said.
Eta, Iota, Kappa and Lambda are also being monitored by the WHO as VOIs.
