The Mu variant is on the rise. Scientists weigh in on how much to worry
Laboratory studies suggest this variant may be better at avoiding the immune system but lags Delta when it comes to transmission and infecting cells.
One of the newest variants of COVID-19, known as Mu, has spread to 42 countries, but early studies suggest that it is less easily transmitted than the dangerous Delta variant, which has triggered a resurgence of the pandemic in the U.S. and many other countries.
Mu quickly became the dominant strain in Colombia, where it was first detected in January, but in the U.S., where the Delta virus is dominant, it has not spread significantly. After reaching a peak at the end of June, the prevalence of the Mu variant in the U.S. has steadily declined.
Scientists believe that the new variant cannot compete with the Delta variant, which is highly contagious. “Whether it could have gone higher or not if there was no Delta, that's hard to really say,” says Alex Bolze, a geneticist at the genomics company Helix.
In Colombia, however, the Mu variant is responsible for more than a third of the COVID-19 cases. There have been 11 noteworthy variants to date, which the World Health Organization has named for the letters of the Greek alphabet. The newest variant, Mu, is the 12th. WHO has labeled this latest version of SARS-CoV-2 a Variant of Interest, a step below a Variant of Concern.
Delta and three other variants have drawn the highest level of concern. But a Variant of Interest, like Mu still raises worries. Mu has many known mutations that can help the virus escape immunity from vaccines or previous infection.
Still, the good news is that Mu is unlikely to replace Delta in places like the U.S. where it is already predominant, says Tom Wenseleers, evolutionary biologist and biostatistician at the Catholic University of Leuven in Belgium, who previously estimated the transmissibility and impact of Alpha variant in England.
How is Mu different?
Most genetic sequences reveal that Mu has eight mutations in its spike protein, many of which are also present in variants of concern: Alpha, Beta, Gamma, and Delta.
Some of Mu’s mutations, like E484K and N501Y, help other variants evade antibodies from mRNA vaccines. In the Beta and Gamma variants, the E484K mutation made the variants more resistant to a single dose of mRNA vaccines.
A study, not yet peer reviewed, has shown that the P681H mutation helps transmission of the Alpha variant—it may do the same for Mu.
Mu also harbors novel mutations that haven’t been seen in variants before, so their consequences are not fully understood. Mutation at the 346 position disrupts interaction of antibodies with the spike protein, which, scientists say, might make it easier for the virus to escape.
A study using epidemiological models, not yet peer reviewed, estimates that Mu is up to twice more transmissible than the original SARS-CoV-2 and caused the wave of COVID-19 deaths in Bogotá, Colombia in May, 2021. This study also suggests that immunity from a previous infection by the ancestral virus was 37 percent less effective in protecting against Mu.
“Right now, we do not have [enough] available evidence that may suggest that indeed this new variant Mu is associated with a significant [..] change in COVID,” says Alfonso Rodriguez-Morales, the President of the Colombian Association of Infectious Diseases.
But some clues are emerging that Mu can weaken protection from antibodies generated by existing vaccines. Lab-made virus mimicking the Mu variant were less affected by antibodies from people who had recovered from COVID-19 or were vaccinated with Pfizer’s Comiranty. In this study, not yet peer reviewed, Mu was the most vaccine resistant of all currently recognized variants.
In another lab-based study, antibodies from patients immunized with Pfizer’s vaccine were less effective at neutralizing Mu compared to other variants.
“[Mu] 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—but there isn’t a lot of clinical data to suggest that. It is mostly laboratory […] data,” said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, at a White House press briefing on September 2.
The COVID-19 vaccines—Pfizer, Astra Zeneca, Johnson & Johnson, and Sinovac, all of which are available in Colombia—still seem to offer good protection against Mu, according to Rodriguez-Morales.
How prevalent is Mu?
The Mu variant rapidly expanded across South America, but it is difficult to know for sure how far Mu has spread, according to Paúl Cárdenas, microbiologist at Universidad San Francisco de Quito in Ecuador.
“[Latin American countries] have provided very low numbers of sequences, compared with the numbers of cases that we have,” says Cárdenas. South American countries have sequenced just 0.07 percent of their total SARS-CoV-2 positive cases, although 25 percent of global infections have occurred in the region. This contrasts with 1.5 percent of all positive cases sequenced in the U.S. and 9.3 percent of all positive cases sequenced in the U.K.
“We are not necessarily looking at the reality of the distribution of the variants [in Latin America], because of the limitations in performing genome sequencing,” says Rodriguez-Morales.
That said, except in Columbia where Mu has been spreading since late February, the variant is becoming relatively less frequent globally, including in the rest of South America.
“Additional evidence on Mu is scarce, similar to Lambda and other regionally prevalent variants, because of limited capacity for follow-up studies, and because these variants have not yet been a significant threat in high-income countries like Delta is,” says Pablo Tsukayama, a microbiologist at Universidad Peruana Cayetano Heredia in Lima, Peru. He hopes the WHO’s designation of Mu as a variant of interest will change that.
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Moderna Announces Development of Combination COVID-19 Booster and Flu Vaccine
Moderna announced on Thursday it had begun development for a potential single-dose vaccine that is a combination of a Wuhan coronavirus vaccine booster shot and seasonal flu shot.
In a press release published Thursday, Moderna CEO Stephane Bancel announced the new development and shared the progress of other programs the company is working on, such as their “cancer vaccine.”
“Today we are announcing the first step in our novel respiratory vaccine program with the development of a single dose vaccine that combines a booster against COVID-19 and a booster against flu,” Bancel said in a statement. “We are making progress on enrolling patients in our rare disease programs, and we are fully enrolled in our personalized cancer vaccine trial. We believe this is just the beginning of a new age of information-based medicines.”
As we previously reported, Moderna informed investors and analysts last month that the company was planning for a booster COVID-19 shot in addition to its already-existing two-dose mRNA vaccine shot. As of right now, the Moderna COVID-19 vaccine was granted Emergency Use Authorization (EUA) by the Food and Drug Administration (FDA) to be administered to prevent the spread of COVID-19. However, the vaccine has not been fully approved by the FDA.
“We are pleased that our COVID-19 vaccine is showing durable efficacy of 93% through six months, but recognize that the Delta variant is a significant new threat so we must remain vigilant,” Bancel said in a statement last month announcing plans for a potential booster shot. In the statement, Bancel also said Moderna is “looking forward towards our vision of a single dose annual booster that provides protection against COVID-19, flu and RSV for adults.”
Perhaps that vision could be on the horizon with this hybrid coronavirus/flu vaccine in the works. Moderna has not revealed when it plans to have the booster shot completed.
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IN BRIEF
RNC to sue Biden administration over vaccine mandates (Washington Examiner)
“We will fight”: Ron DeSantis promises to battle Biden’s sweeping mandates (Daily Wire)
Pentagon top brass to testify before Senate panel on chaotic U.S. pullout from Afghanistan (Washington Times)
GOP letter to Biden flags Afghan evacuees’ “rushed and incomplete” vetting (Fox News)
Taliban lets plane carrying Americans and other foreign nationals leave Kabul (CBS News)
“Their interior minister has an ‘FBI Wanted’ poster”: White House challenged after calling Taliban “businesslike and professional” (Daily Caller)
New and improved? Hardly: Taliban tortured journalists who covered protests in Kabul despite “free press” pledge (Daily Wire)
Fort Hood terrorist congratulates Taliban from death row in handwritten letter (Washington Examiner)
Merrick Garland’s Justice Department suing Texas over pro-life law (The Federalist)
Rand Paul calls for Anthony Fauci to be jailed for lying to Congress (Washington Examiner)
DOJ moves to release FBI documents on investigation into possible Saudi-9/11 hijacker links (Washington Examiner)
Team Biden puts systemic racism at center of U.S. foreign policy (National Review)
The CDC quietly changed the definition of “vaccination” so as to fit the political narrative (Not the Bee)
FDA declines emergency use authorization for Humanigen COVID-19 drug (The Hill)
https://patriotpost.us/articles/82600-friday-executive-news-summary-2021-09-10
******************************************Also see my other blogs. Main ones below:
http://edwatch.blogspot.com (EDUCATION WATCH)
http://antigreen.blogspot.com (GREENIE WATCH)
http://pcwatch.blogspot.com (POLITICAL CORRECTNESS WATCH)
http://australian-politics.blogspot.com/ (AUSTRALIAN POLITICS
http://snorphty.blogspot.com/ (TONGUE-TIED)
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