Mu variant: what you need to know about the UK’s new strain of COVID

There was a new case of the Mu variant of interest in England In the week leading up to September 15, 2021, the British government confirmed. This brings the total number of mu cases in the UK to 54.

Although this is the first new case since September 3, Public Health England and the World Health Organization (WHO) are still closely monitoring the strain.

Some scientists have warned that the Mu strain, also known as B.1.621, could pose a problem if it were to become the dominant variant. This is because the mu variant can more easily spread through cells in the human body, which can also be seen in the delta variant.

This result comes from a pre-print paper, so it is inconclusive and has not been assessed by experts.

The researchers, who are based at Yokohama City University School of Medicine in Japan, say that having the same cell locomotion trait as Delta but a higher percentage of escape from the vaccine means “mu could be especially a problem when it is.” that would replace “Delta as the predominant variant”.

“Even so, the current vaccines and antibody cocktail would still work for the majority, albeit with slightly less efficacy than is currently observed with the Delta variant,” they say.

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“The Mu variant was first reported in Colombia in January.” Dr. Paul Cardenas, an infectious disease specialist, said Science focus of the BBC. “We found it in Ecuador in May. It caught our attention because it has several mutations that are similar to beta, and some with iota, delta, alpha, and eta. “

Cárdenas says that within a few weeks, the Mu variety displaced the most common varieties in Ecuador before Mu’s arrival.

“It has been found in many other countries in South America, including Peru, Uruguay, Bolivia, Paraguay and Uruguay, and there have been small outbreaks of this variant in Spain, France and Florida, USA.”

Why was mu called an interesting variant?

The Mu strain carries several mutations to the spike gene.

An article published in the Journal of Medical Virology notes that some of Mu’s mutations are found in other worrying variants while others are new. Researchers who have studied the spread of mu in Italy say the strain has mutations that are also found in the affected alpha, beta, and gamma variants.

According to European Center for Disease Prevention and Control, the Mu variant also carries a mutation that can be found in the Delta variant.

A map of the occurrence of the B.1.621 Mu variant of the coronavirus, as of September 17, 2021 © cov-lineages.or

the Variant of the WHO denomination of interests means that the trunk:

  • genetic changes that are predicted or known to affect viral properties such as communicability, disease severity, immune discontinuation, diagnostic or therapeutic exit
  • Identified over time in several countries with increasing relative prevalence and increasing numbers of cases to cause significant community transmission or multiple clusters of COVID-19
  • may have other obvious epidemiological impacts that indicate an emerging risk to global public health.

How many cases of the mu variant have been detected in the UK?

According to the UK government, there have been a total of 54 cases of the Mu COVID variant in the UK. This breaks down into 48 cases in England, 3 in Scotland, 2 in Northern Ireland and 1 in Wales.

The strain was named VUI-21JUL-01 by Public Health England.

Do vaccines still work against the mu variant?

There is not yet enough evidence to conclusively say whether the mu variant can evade protection from coronavirus vaccines.

The Japan study, published September 26, 2021, tested the effectiveness of the BioNTech Pfizer vaccine against the Mu variant.

The study used samples from people who had received a double vaccination and were collected one week after their second dose.

The researchers found that while the Pfizer vaccine’s effectiveness was reduced to 79 percent (compared to 96 percent effectiveness in neutralizing the original strain of COVID-19), it “still has adequate ability to handle the majority of the To neutralize vaccines ”. [variants]”.

One in. published study The Lancet Infectious Diseases on August 13, 2021 suggests that the Mu variant “two cases of possible vaccination escape“.

They write that several of the spike mutations within Mu “show reduced neutralization by antibodies”.

The Mu variant was also found to have the same spike mutation that was linked to a weakened vaccination response in the beta variant.

“The presence of mutations related to the leak of the vaccine could warrant reclassification of this variant to a variant of concern.”

Is the mu Variant more transferable?

There are currently very few studies looking at the mu variant. Since research on this particular variant is still at an early stage, it is too early to know whether the stress is more transferable or heavier than other variants.

A pre-print study found that the mutations in the strain B.1.621 could have “a synergistic effect on the attributes” such as reducing vaccine-induced protection against serious illness, increasing transmission and severity of illness ”.

What are the symptoms of the mu Variant?

The mu variant appears to have the same symptoms as all other coronavirus strains. the Main symptoms of COVID-19, according to the NHS are:

  • a high temperature – this means that you feel hot on your chest or back (you do not need to take your temperature)
  • a new, persistent cough – this means a lot of coughing for more than an hour or three or more fits of coughing in a 24 hour period (if you cough normally it may be worse than usual)
  • a loss or change in your sense of smell or taste – this means that you have noticed that you cannot smell or taste anything, or that things smell or taste differently than normal

The NHS says most people who have symptoms of COVID-19 will have at least one of the above.

What other variants have been identified in the UK?

From September 17, 2021 there will be five Strains classified as “Concerning” by PHE, including the Delta and Alpha variants.

The PHE monitor a total of 16 variants.

BBC Science Focus asked PHE to comment on the spread of Mu.

About our expert Dr. Paul Cardenas

Dr. Cárdenas is Associate Professor at the Institute of Microbiology at the University of San Francisco de Quito. He has a PhD in Genomic Medicine from Imperial College London and has published several articles on the pandemic for the detection and spread of COVID variants.