Mu is the fifth COVID-19 variant to be detected since March 2021. It was first identified in Colombia in January 2021. Nonetheless, it has now been confirmed in at least 39 countries.

“Mu has a constellation of mutations that indicate potential properties of immune escape. Preliminary data presented to the Virus Evolution Working Group show a reduction in neutralization capacity of convalescent and vaccine sera similar to that seen for the Beta variant, but this needs to be confirmed by further studies,” says the WHO.

Since the variant has genetic mutations, it halts the natural immunity as well as monoclonal antibody treatments . However, further studies are mandated to prove the contagiousness, deadly nature, and resistance to current vaccines and treatments.

Global Prevalence

As the infection rates are reaching their heights globally again with the highly transmissible Delta variant, there is a broad concern over the evolution of new virus mutations. The global prevalence of the Mu variant has been declined and is currently below 0.1% among sequenced cases.

But the cases in Colombia (39%) and Ecuador (13%) have shown a steady uptick in its prevalence. Experts around the world are on a quest to explore if the Mu variant is more transmissible and dangerous than the Delta variant.

“The epidemiology of the Mu variant in South America, particularly with the co-circulation of the Delta variant, will be monitored for changes,” says WHO.

Viral Mutation

Any change in the genetic material of an organism, such as damaged DNA causes mutation. It results in the alteration of the genetic message carried by that gene. Generally, all the viruses, including SARS-CoV-2 mutate over time.

These genetic mutations may have little or no effect on the properties of the virus. However, certain mutations may impact the viral properties and influence the severity of the disease. These changes may also cause resistance to vaccines, drugs, and other countermeasures.

With few reports on the phenotypic and clinical characteristics of the Mu variant currently, the WHO issues a warning against the ‘immune escape’ ability of the variant to overcome vaccine protection.

Rising Numbers of Mu Variant

Over the past four weeks with 4,500 genome sequences (3,794 B.1.621 sequences and 856 B.1.621.1 sequences) analyzed, the data designated these samples as Mu variants. These sequence data help track the movement of this virus through the community on GISAID, an open-source genome repository.

The larger outbreaks of the Mu variant were reported in South America, and Europe, along with the cases being reported in the US, UK, and Hong Kong. So far, the United States has recorded 4000 cases of the Mu variant.

The pattern of infections in the UK depicts that it was brought in by travelers on multiple occasions especially in London and in people in their 20s as per a report by Public Health England (PHE) in July.

The variant C.1.2 has been found in countries like China, the Democratic Republic of the Congo, Mauritius, England, New Zealand, Portugal, and Switzerland.

Alarming Concern

The PHE has included the new variant into the list of variants under investigation as VUI-21JUL-01 in July. This involves periodical monitoring of the variant for its behavior.

The risk assessment of the Mu variant by the PHE (August 2021) suggested that the variant is at least as resistant as the Beta variant to coronavirus immunity.

The concerns of viral mutations carried by the Mu variant include the P681H mutation (faster transmission) that was found in the Alpha variant. The others include E484K and K417N mutations (which may help the virus evade immunity defenses).

However, laboratory studies and real-world cases (with faster spreading capacity) of the variant are required to draw further conclusions.

“At present, there is no evidence that VUI-21JUL-01 is outcompeting the Delta variant and it appears unlikely that it is more transmissible,” the report states, though it goes on to warn: “Immune escape may contribute to future changes in growth.”

Reference:

1. Tracking SARS-CoV-2 variants
   – (https://www.who.int/en/activities/tracking-SARS-CoV-2-variants/)

Source: Medindia