SARS-CoV-2 variants of concern are associated with lower RT-PCR amplification cycles between January and March 2021 in France

SARS-CoV-2 variants raise concern regarding the mortality caused by COVID-19 epidemics. We analyse 88,375 cycle amplification (Ct) values from variant-specific RT-PCR tests performed between January 26 and March 13, 2021. We estimate that on March 12, nearly 85% of the infections were caused by the Alpha variant and that its transmission advantage over wild type strains was between 38 and 44%. We also find that tests positive for Alpha and Beta/Gamma variants exhibit significantly lower cycle threshold (Ct) values. (C) 2021 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.

Automated summary

The analysis of 88,375 cycle amplification (Ct) values revealed that the Alpha variant of SARS-CoV-2 had a transmission advantage over wild type strains, causing a rapid increase in infections. Additionally, tests positive for Alpha and Beta/Gamma variants showed significantly lower Ct values, indicating higher viral loads.