The World Health Organisation (WHO) has said it is monitoring a new variant of the coronavirus known as 'Mu'.

The B.1.621 strain was first identified in Colombia and a smattering of cases have been recorded in South America and Europe. It's now been listed as one of five variants of interest by the WHO.

That means that while the global health agency considers it worthy of special monitoring, it's viewed as less of a potential problem than the Delta or Alpha strains of the SARS-CoV-2 virus, which have been designated variants of concern due to their increased virulence.

What are variants of interest?

The World Health Organisation has classified each emerging variant as either a Variant of Concern (VOC) or a Variant of Interest (VOI). The Alpha, Beta, Gamma and Delta variants fall under Variants of Concern. Whereas the Eta, Iota, Kappa, Lambda, and now Mu, fall under Variants of Interest.

According to WHO, a VOI is a SARS CoV-2 variant with a genetic capability that affects characteristics of the virus such as disease severity, immune escape, transmissibility and diagnostic escape.

The world health body further confirmed that a VOI causes a consequential volume of community transmission. A global increase in cases poses a risk of large proportions to worldwide public health.

A VOC, meanwhile, translates to a rise in transmissibility, an increase in fatality and a significant decrease in effectiveness of vaccines, therapy and other health measures.

What is known about the Mu variant?

The WHO’s weekly bulletin on the pandemic said that while the Mu variant accounts for only a small percentage of global cases, scientists are studying whether it could have properties that would help it get past immune protections built up by vaccination or past infection.

This was also the case with the Beta variant, first discovered in South Africa, but the WHO has said more studies will be needed to examine this new strain further.

Mu is scientifically known as B.1.621 and has been classified as a "variant of interest"

The bulletin said: “Since its first identification in Colombia in January 2021, there have been a few sporadic reports of cases of the Mu variant and some larger outbreaks have been reported from other countries in South America and in Europe.

“Although the global prevalence of the Mu variant among sequenced cases has declined and is currently below 0.1 per cent, the prevalence in Colombia (39 per cent) and Ecuador (13 per cent) has consistently increased.

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

Why emerging variants are significant even if they are not widespread

The number of variants of SARS-CoV-2 should be expected to change over time, because the more the virus spreads, the more opportunities it has to mutate.

The changes in the variants occur when there is a mutation of the genes of the virus

Whenever the Covid-19 virus infects someone, it hijacks the biological machinery of their cells to create copies of itself. Every so often the genetic material the virus carries is copied incorrectly, producing what is known as a mutation.

All viruses, including SARS-CoV-2 that causes Covid-19, mutate over time and most mutations have little or no effect on the properties of the virus.

But certain mutations can impact the properties of a virus and influence how easily it spreads, the severity of the disease it causes, and its resistance to vaccines, drugs and other countermeasures.

The emergence of new strains is of much importance to the scientific fraternity as strains are the virus's response to vaccines. Hence, chances are there that new variants may neutralise vaccines.