We have seen several variants of the original coronavirus SARS-CoV-2 in different parts of the world since the beginning of the COVID-19 pandemic. Some were deadly like the Delta variant, which gradually became the dominant strain of the coronavirus. While variants like Delta significantly increased infection rates in many countries, some others remained restricted to a smaller region, falling short of causing any major outbreak.
The World Health Organization (WHO) added another name to this list of variants, which is the Mu variant (B.1.621), which was found in Columbia in January. The WHO added this strain to its list “Variants of Interest” on Aug 30.
The alarming list contains new variants with genetic changes that can affect transmissibility, disease severity, immune escape and other virus characteristics. These are identified to cause significant community transmission. The Mu variant has reportedly spread to some South American and European countries following its first appearance in Columbia.
Although infected cases due to the Mu variant remain significantly less than the coronavirus strains listed on the WHO’s “Variants of Concern” list, the global health authority is monitoring the impact of this mutant on public health, immune response and the effectiveness of the COVID-19 vaccines/therapeutics.
The “Variants of Concern” list currently contains four variants, namely Alpha, Beta, Gamma and Delta, which were first detected in the United Kingdom, South Africa, Brazil and India, respectively. These strains demonstrated higher transmissibility and decrease in the effectiveness of vaccines.
How Does Mu Compare With Delta?
The Mu variant has been found in some Latin American and European countries so far while the Delta variant is present in more than 170 countries across the globe.
The Delta variant strain already wreaked havoc on public health in many nations including India and United States with its high transmissibility rate. Moreover, effectiveness of authorized vaccines — Moderna’s (MRNA Quick QuoteMRNA ) mRNA-1273, Pfizer’s (PFE Quick QuotePFE ) Comirnaty and the COVID-19 vaccines of J&J (JNJ Quick QuoteJNJ ) and AstraZeneca (AZN Quick QuoteAZN ) — are found to have reduced against the Delta variant in clinical studies.
Data from a study conducted in Japan showed that the Mu variant can become highly resistant to vaccines, per bioRxiv preprint.
Unavailability of sufficient data makes the comparison of Mu variant with the Delta strain or other variants difficult. However, the WHO dubbed the Delta variant as the most fatal variant, per a CNBC article. The global health organization stated that more studies need to be conducted to understand the clinical characteristics of the Mu variant. New diagnostics and vaccines are required to be developed if the variant becomes a cause for concern.
Per MarketWatch article, White House chief medical adviser Dr. Anthony Fauci believes that the Mu variant is not an immediate threat to the country and the Delta mutant is still ruling the roost in transmitting the infection. However, the Mu variant will be closely watched, he assured.