Transmissability: Likely Increased.
Virulence: Likely Increased.
Antigenicity: Mu variant has mutations that have the potential to evade immunity provided by a previous COVID-19 infection or vaccination.
Spread: Outbreaks of the Mu variant were reported in South America and Europe. The lineage B.1.621 has a sublineage, labeled B.1.621.1 under the PANGO nomenclature, which has already been detected in more than 20 countries worldwide.
Global Positive Samples Sequenced: 3,256,369
B.1.621 Sequenced: 3,624
% of Global Samples Sequenced: 0.11%
Distribution of B.1.621 Sequences Top 5 Countries: United States of America 46.0%, Colombia 13.0%, Mexico 10.0%, Spain 10.0%, Ecuador 4.0% – 3624
Distribution of B.1.621.1 Sequences Top 5 Countries: United States of America 63.0%, Spain 13.0%, Austria 5.0%, Dominican_Republic 5.0%, Switzerland 3.0% – 898
Updated September 2021