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arXiv · 2108.10018

Mutational signatures and transmissibility of SARS-CoV-2 Gamma and Lambda variants

Karen Y. Oróstica·Sebastian Contreras·Sebastian B. Mohr·Jonas Dehning·Simon Bauer·David Medina-Ortiz·Emil N. Iftekhar·Karen Mujica·Paulo C. Covarrubias·Soledad Ulloa·Andrés E. Castillo·Ricardo A. Verdugo·Jorge Fernández·Álvaro Olivera-Nappa·Viola Priesemann
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Abstract

The emergence of SARS-CoV-2 variants of concern endangers the long-term control of COVID-19, especially in countries with limited genomic surveillance. In this work, we explored genomic drivers of contagion in Chile. We sequenced 3443 SARS-CoV-2 genomes collected between January and July 2021, where the Gamma (P.1), Lambda (C.37), Alpha (B.1.1.7), B.1.1.348, and B.1.1 lineages were predominant. Using a Bayesian model tailored for limited genomic surveillance, we found that Lambda and Gamma variants' reproduction numbers were about 5% and 16% larger than Alpha's, respectively. We observed an overabundance of mutations in the Spike gene, strongly correlated with the variant's transmissibility. Furthermore, the variants' mutational signatures featured a breakpoint concurrent with the beginning of vaccination (mostly CoronaVac, an inactivated virus vaccine), indicating an additional putative selective pressure. Thus, our work provides a reliable method for quantifying novel variants' transmissibility under subsampling (as newly-reported Delta, B.1.617.2) and highlights the importance of continuous genomic surveillance.

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Karen Y. Oróstica, Sebastian Contreras, Sebastian B. Mohr, Jonas Dehning, Simon Bauer, David Medina-Ortiz, Emil N. Iftekhar, Karen Mujica, Paulo C. Covarrubias, Soledad Ulloa, Andrés E. Castillo, Ricardo A. Verdugo, Jorge Fernández, Álvaro Olivera-Nappa, Viola Priesemann. 2021-08-23. Mutational signatures and transmissibility of SARS-CoV-2 Gamma and Lambda variants. https://arxiv.org/abs/2108.10018

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