Early transmissibility assessment of the N501Y mutant strains of SARS-CoV-2 in the United Kingdom, October to November 2020

Two new SARS-CoV-2 lineages with the N501Y mutation in the receptor-binding domain of the spike protein spread rapidly in the United Kingdom. We estimated that the earlier 501Y lineage without amino acid deletion Delta 69/Delta 70, circulating mainly between early September and mid-November, was 10% (6-13%) more transmissible than the 501N lineage, and the 501Y lineage with amino acid deletion Delta 69/Delta 70, circulating since late September, was 75% (70-80%) more transmissible than the 501N lineage.

Automated summary

Two new lineages of SARS-CoV-2 with the N501Y mutation in the receptor-binding domain of the spike protein have spread rapidly in the United Kingdom. The 501Y lineage without amino acid deletion Delta 69/Delta 70 was estimated to be 10% more transmissible than the 501N lineage, while the 501Y lineage with amino acid deletion Delta 69/Delta 70 was estimated to be 75% more transmissible than the 501N lineage.