SARS-CoV-2 Alpha variant

The Alpha variant (B.1.1.7) was a SARS-CoV-2 variant of concern. It was estimated to be 40–80% more transmissible than the wild-type SARS-CoV-2 (with most estimates occupying the middle to higher end of this range). Scientists more widely took note of this variant in early December 2020, when a phylogenetic tree showing viral sequences from Kent, United Kingdom looked unusual.

The variant began to spread quickly by mid-December, around the same time as infections surged. This increase is thought to be at least partly because of one or more mutations in the virus' spike protein. The variant was also notable for having more mutations than normally seen. By January 2021, more than half of all genomic sequencing of SARS-CoV-2 was carried out in the UK. This gave rise to questions as to how many other important variants were circulating around the world undetected.

On 2 February 2021, Public Health England reported that they had detected "[a] limited number of B.1.1.7 VOC-202012/01 genomes with E484K mutations", which they dubbed Variant of Concern 202102/02 (VOC-202102/02). One of the mutations (N501Y) was also present in Beta variant and Gamma variant. On 31 May 2021, the World Health Organization announced that the Variant of Concern would be labelled "Alpha" for use in public communications.

The Alpha variant disappeared in late 2021 as a result of competition from even more infectious variants. In March 2022, the World Health Organization changed its designation to "previously circulating variant of concern".^{[citation needed]}

The variant is known by several names. Outside the UK it is sometimes referred to as the UK variant or British variant or English variant, despite the existence of other, less common, variants first identified in UK, such as Eta variant (lineage B.1.525). Within the UK, it is commonly referred to as the Kent variant after Kent, where the variant was found.

In scientific use, the variant had originally been named the first Variant Under Investigation in December 2020 (VUI – 202012/01) by Public Health England (PHE), but was reclassified to a Variant of Concern (Variant of Concern 202012/01, abbreviated VOC-202012/01) by Meera Chand and her colleagues in a report published by PHE on 21 December 2020. In a report written on behalf of COVID-19 Genomics UK (COG-UK) Consortium, Andrew Rambaut and his co-authors, using the Phylogenetic Assignment of Named Global Outbreak Lineages (pangolin) tool, dubbed it lineage B.1.1.7, while Nextstrain dubbed the variant 20I/501Y.V1.

The name VOC-202102/02 refers to the variant with the E484K mutation (see below).

Mutations in SARS-CoV-2 are common: over 4,000 mutations have been detected in its spike protein alone, according to the COVID-19 Genomics UK (COG-UK) Consortium.