World Health Organization bosses are now officially following another Covid variant called ‘Mu’.
The mutated strain — which also goes by the scientific name B.1.621 — was first discovered in Colombia in January.
Since then, nearly 4,000 cases have been reported and it has spread to more than 40 countries.
Nearly 50 cases of Mu have been reported so far in the UK and hundreds have been identified in the US.
The WHO’s weekly bulletin claimed its mutations suggest it may be more resistant to vaccines, as was the case with the South African ‘beta’ variant. There are fears it may also be more contagious.
But the agency warned that more studies would be needed to investigate this further, now that the WHO has formally labeled Mu a “variant of interest.”
Nearly 4,000 cases of the variant have been detected so far since its introduction in January, but the number of infections has fallen in recent weeks, coinciding with the rapid increase in the Delta variant. This chart shows the seven-day average number of cases worldwide attributable to the Mu variant. They Reveal That Prevalence Has Fallen Recently
The variant was first spotted in Colombia in January. It has since been detected in 40 countries
According to Public Health England, some 48 cases have been detected so far
Nearly 50 cases have been reported in Britain so far. But these have generally remained low amid the spread of the Delta variant. The graph above shows the B.1.621 variant as a percentage of all cases detected in the UK by date
In the US it accounted for almost one percent of the infections in July, but the number of infections then decreased in August due to the spread of the Delta variant.
In Colombia — where it was first identified — it still lags behind about six in 10 cases. But the proportion of cases it covers in the country is also starting to decline
The WHO report said: “Since the first identification in Colombia in January 2021, there have been some sporadic reports of cases of the Mu variant and some larger outbreaks have been reported from other countries in South America and in Europe.
“While the global prevalence of the Mu variant among sequenced cases has declined and is currently below 0.1 percent, the prevalence in Colombia (39 percent) and Ecuador (13 percent) has steadily increased.
What is the variant ‘Mu’ or B.1.621?
Where have the cases been identified?
This mutated species was first spotted in Colombia in January.
Since then, it has spread to over 40 countries, including the UK, US, France, Japan and Canada.
Is the prevalence rising?
4,000 cases have been detected so far, but this is considered an underestimate as many countries that have suffered from outbreaks have very little monitoring of variants.
The number of cases attributed to the variant dropped worldwide last month, amid the spread of the Delta strain.
In Colombia – where it was first discovered – it still lags behind about six in ten infections.
Can the strain evade the vaccine that causes immunity?
The variant carries the mutation E484K, which allows it to escape antibodies.
This change can also be found on the South African ‘Beta’ variant and the Brazilian ‘Gamma’ variant.
A PHE study previously suggested it could make vaccines less effective. But UK health leaders said more research was needed.
‘The epidemiology of the Mu variant in South America, especially in the co-circulation of the Delta variant, will be monitored for changes.’
The WHO currently lists four worrisome Covid variants: Alpha, Beta, Gamma and the highly transmissible Delta.
Mu is the fifth interesting variant and is followed alongside Eta, Iota, Kappa and Lambda.
There is “no evidence” to suggest the variant is more transmissible than the dominant Delta strain, Public Health England said last month.
Infectious disease epidemiologist at WHO Maria van Kerkhove tweeted: “The circulation of Mu has declined worldwide and the [makes up] less than 0.1 percent of the currently shared sequences of Mu, but this requires careful observation.”
“Monitoring and assessment of variants is ongoing and critical to understand the evolution of this virus, fight Covid and adapt strategies where necessary.”
British health chiefs have upgraded the strain to a variety to be studied in July.
So far, about 48 cases have been discovered.
The most important mutations include E484K, which can aid in the escape of antibodies and is also found in the beta and gamma variants.
It also has the N501Y, which could help it spread more easily. This mutation is also present in Alpha.
The coronavirus, called SARS-CoV-2, constantly mutates as a result of genetic errors as it multiplies. Most mutations are harmless.
But the ones that allow it to spread faster or survive longer in the human body are the ones that are likely to stick around.
More than 300 Covid variants have been detected so far.
It comes after a report from PHE published in early August suggested Covid shots may be “less effective” against the mutated strain.
But they said their findings were based on preliminary lab evidence, so the data was “very limited and more research is needed.”
Their report added that there was “no evidence” to suggest the variant is more transmissible than the Delta strain.
The report states: ‘The degree of threat posed by such a variant depends on its growth and expansion.
“There is currently little certainty about the growth estimates, but in the current context there is no indication that it will outperform Delta.”