What’s ‘Mu’ strain of Covid? From evading vaccine to transmissibility, everything we know about new Corona variant

The World Health Organisation is closely monitoring another Covid-19 variant, termed as Mu or B.1.621 that might emerge as a variant of concern in recent future as it showed signs of possible resistance to vaccines.

Where had the new Mu variant originated

The variant of interest was first identified in Columbia in January 2021 and since then there were reports of sporadic rise in cases, larger outbreaks in and around Europe and South America, the UN health agency’s weekly bulletin said.

Over 4,500 samples were genome sequenced as on August 29 and analysed samples were designated as Mu. The most cases were detected from the US followed by Columbia, Mexico and then Span. Cases of the new variant of interest were also reported in the UK, Europe and Hong Kong.

Why it is on WHO’s watchlist

The variant was added to WHO’s watchlist on August 30 after Covid cases with the same variant were found in 39 countries. On genome sequencing it was found that the variant went through a constellation of mutations that indicate potential properties that can make it evade immune response from vaccination.

The prevalence of the sequenced cases is the highest in Columbia at 39% and then Ecuador at 13% e of the Mu variant even when its global prevalence is below 0.1 per cent currently.

The Mu variant also of the B.1.621 lineage was under WHO’s scanner since March for undergoing a number of mutations that makes it vaccine resistant, but said that further research is required to affirm the same. According to WHO, more studies were required to understand its phenotypic and clinical characteristics. According to the preliminary data, the variant escapes immune defences similar to beta variants first found in South Africa.

Mu variant is resistant to vaccine as Beta: PHE report

According to a risk management of the new variant report released by Public Health England, the variant can resist immunity formed from vaccination at least as much as the Beta variant. Moreover, WHO’s preliminary studies show that the new variant can also evade the natural immunity formed by a body due to earlier infection in addition to immunity formed by vaccination.

Is Mu variant more transmissible?

A report by the Guardian says there is so far no evidence that supports that it is outcompeting the Delta variant and it appears unlikely that it is more transmissible. But immune escape can dictate how it spreads in a population in future. The threat the Mu variant now poses depends on whether cases grow substantially in coming weeks and months.

Another coronavirus variant C.1.2 detected

Meanwhile, another potential variant of interest, C.1.2 is being closely monitored in South Africa. The cases were first detected in the country in May this year and then where found in England, New Zealand, Switzerland, Portugal, China, Mauritius and the Democratic Republic of the Congo.

However, C.1.2 has not been raised as a variant to follow or of concern by WHO. So far, WHO has classified four variants of concern – Alpha, Beta, Delta and Gamma – along with five variants of interest, including Mu.