Early assessment of diffusion and possible expansion of SARS-CoV-2 Lineage 20I/501Y.V1 (B.1.1.7, variant of concern 202012/01) in France, January to March 2021

Euro Surveill. 2021 Mar;26(9):2100133. doi: 10.2807/1560-7917.ES.2021.26.9.2100133.


The emergence of SARS-CoV-2 variant 20I/501Y.V1 (VOC-202012/1 or GR/501Y.V1) is concerning given its increased transmissibility. We reanalysed 11,916 PCR-positive tests (41% of all positive tests) performed on 7-8 January 2021 in France. The prevalence of 20I/501Y.V1 was 3.3% among positive tests nationwide and 6.9% in the Paris region. Analysing the recent rise in the prevalence of 20I/501Y.V1, we estimate that, in the French context, 20I/501Y.V1 is 52-69% more transmissible than the previously circulating lineages, depending on modelling assumptions.

Keywords: 20I/501Y.V1; COVID; France; SARS-CoV-2; mutation; surveillance; viral infections.

MeSH terms

  • COVID-19* / epidemiology
  • France / epidemiology
  • Humans
  • Paris
  • SARS-CoV-2*

Supplementary concepts

  • SARS-CoV-2 variants