SARS-CoV-2 Mu variant
variant of SARS-CoV-2 discovered in January 2021 in Colombia
The Mu variant (B.1.621) is a variant of SARS-CoV-2. It was first detected in Colombia in January 2021 and was classified by the World Health Organization (WHO) as a variant of interest on August 30, 2021. On March 9, 2022, the WHO de-escalated the Mu variant and its subvariants to previously circulating variants of interest.
The B.1.621 lineage has a sublineage, designated B.1.621.1 under the PANGOLIN nomenclature, which has also been detected in multiple countries worldwide.
Classification
Within the PANGOLIN naming scheme, the variant was designated as B.1.621. On July 1, 2021, Public Health England designated the lineage as a variant under investigation (VUI), calling it VUI-21JUL-1. On August 30, 2021, it was classified as a variant of interest (VOI) by the World Health Organization (WHO) and assigned it the name Mu, following their Greek-letter naming system.
The lineage, including its sublineage B.1.621.1, is assigned to Nextstrain clade 21H and GISAID clade GH. On March 9, 2022, the WHO reclassified the Mu variant as a previously circulating VOI as it has been demonstrated to no longer pose a substantially greater risk to global public health compared to other circulating SARS-CoV-2 variants.
Mutations
With outbreaks of the Mu variant reported in South America and Europe since detection, the WHO said the Mu variant has a "constellation of mutations that indicate potential properties of immune escape" or a risk of resistance to the current vaccines, noting that preliminary studies showed signs of this while stressing that further studies are needed to confirm and better understand it.
The Mu genome has a total number of 21 mutations, including 9 amino acid mutations, all of which are in the virus's spike protein code: T95I, Y144S, Y145N, R346K, E484K or the escape mutation, N501Y, D614G, P681H, and D950N. It has an insertion of one amino acid at position 144/145 of the spike protein, giving a total mutation YY144–145TSN, in addition to an insertion N at position 146.
“SARS-CoV-2 Mu variant” enters the record as variant of SARS-CoV-2 discovered in January 2021 in Colombia. Crown Archives preserves that source wording while asking what SARS-CoV-2, variant and discovered can confirm, complicate or overturn.
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