The World Health Organization announced late Tuesday into Wednesday that it is monitoring a new mutated version of the coronavirus named "Mu," which was first detected in Colombia last January. In its weekly epidemiological bulletin on the development of the pandemic, the organization stated that the variant, scientifically designated as "B.1.621," is currently classified as a "variant of interest."
The organization clarified that this variant has mutations that could pose a risk of "immune escape" (i.e., resistance to vaccines), making it essential to conduct further studies to better understand its characteristics. All viruses, including SARS-CoV-2, the cause of COVID-19, mutate over time. While the vast majority of mutations have little or no effect on the virus's properties, some mutations can influence characteristics such as increasing ease of transmission, severity of the resulting illness, or resistance to vaccines, treatments, diagnostic tools, or other public health measures.
Due to the emergence of variants in late 2020 that posed an increasing threat to public health, the World Health Organization established a list of variants that should be monitored and those that are concerning, in order to prioritize global surveillance and research activities. The World Health Organization decided to name variants that need monitoring and those that are concerning using letters from the Greek alphabet instead of the name of the country where they were first identified, to avoid stigmatizing that country and to simplify pronunciation for the public.
Currently, according to the World Health Organization, there are four concerning variants including the Alpha variant, which has spread to 193 countries, and the Delta variant, which has spread to 170 countries, while there are five other variants that need to be monitored (including the "Mu" variant).
The "Mu" variant was first detected in Colombia in January. Since then, infections have been reported in several countries across Latin America and Europe. The World Health Organization noted that "although the global spread of the Mu variant among sequenced cases has declined and is currently below 0.1%, its spread in Colombia (39%) and Ecuador (13%) is steadily increasing."
