What’s new about Mu?
Mu is a version of the coronavirus that was first identified in Colombia in January and has since caused isolated outbreaks in South America, Europe, and the United States.
The World Health Organization last month listed it as a “variant of interest” because of concerns it may make vaccines and treatments less effective though more evidence is needed.
Scientists monitor emerging COVID-19 variants based on suspicious genetic changes and then look for evidence to determine whether the new version is more infectious or causes more severe illness. Viruses evolve constantly, and many new variants often fade away.
So far, the Mu variant doesn’t seem to be spreading quickly: It accounts for fewer than one per cent of COVID-19 cases globally. In Colombia, it may be responsible for about 39 per cent of cases. Most countries remain concerned about the highly contagious Delta variant. It is the dominant variant in almost all of the 174 countries where it has been detected.
A report from England’s public-health agency last month suggested that the Mu variant might be as resistant to vaccines as the worrisome Beta variant first seen in South Africa but said more real-world data was needed.
WHO officials said that the Mu variant appears to be rising in some countries in South America but that the Delta variant still spreads far more easily.