The World Health Organisation (WHO) is closely watching a new coronavirus variant, termed Mu or B.1.621, after it showed signs of possible resistance to vaccines.
Mu has been classified as one of five variants of interest, while there are four variants of concern – Alpha, Beta, Delta and Gamma.
Since being first identified in Colombia in January 2021, there have been “sporadic reports” of Mu cases in some South American and European countries, WHO said in its weekly bulletin.
Till August 29, over 4,500 sequences, genome sequences and analyzed samples of virus taken from patients have been designated as ‘Mu’ over the last four weeks. A majority of these cases have been reported in the US (2,065) and Colombia (852), Mexico (357) and Spain (473).
WHO informed that this new variant was included in its watchlist on August 30 after it was detected in 39 countries and found to possess a “constellation of mutations that indicate potential properties of immune escape”.
Mu variant’s global prevalence is under 0.1%, but in countries like Colombia (39%) and Ecuador (13%), it has increased.
B.1.621, the fifth variant of interest to be monitored by WHO since March, has a number of mutations which lead to the possibility that it could be more resistant to vaccines, WHO has warned.
“More studies are required to understand the phenotypic and clinical characteristics of this variant,” WHO added.
According to preliminary data, Mu may evade immune defences like Beta variant which first found in South Africa.
