

Laurent Gillieron | Reuters
The World Health Organization is monitoring a new coronavirus variant called “mu,” which the agency says has mutations that have the potential to evade immunity provided by a previous Covid-19 infection or vaccination.
Mu — also known by scientists as B.1.621 — was added to the WHO’s list of variants “of interests” on August 30, the International Health Organization said in its weekly Covid epidemiological report published late Tuesday.
The variant contains genetic mutations that indicate natural immunity, current vaccines or monoclonal antibody treatments may not work as well against it as they do against the original ancestral virus, the WHO said. The mu strain needs further study to confirm whether it will prove to be more contagious, more deadly or more resistant to current vaccines and treatments.
There is widespread concern over the emergence of new virus mutations as infection rates are ticking up globally again, with the highly transmissible Delta variant taking hold – especially among the unvaccinated – and in regions where anti-virus measures have been relaxed.
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 WHO currently identifies four COVID-19 variants of concern, including Alpha, which is present in 193 countries, and Delta, present in 170 countries.
Five variants, including Mu, are to be monitored.
After being detected in Colombia, Mu has since been reported in other South American countries and in Europe.
The WHO said its global prevalence has declined to below 0.1 per cent among sequenced cases. In Colombia, however, it is at 39 per cent.