Genomic Surveillance and Molecular Characterization of SARS-CoV-2 Variants During the Peak of the Pandemic in Türkiye

Abstract

SARS-CoV-2 is a highly transmissible coronavirus and has caused a pandemic of acute respiratory disease. Genomic characterization of SARS-CoV-2 is important for monitoring and assessing its evolution. A total of 1.346 nasopharyngeal swab samples were collected but only 879 SARS-CoV-2 high-quality genomes were isolated, subjected to Next Generation Sequencing and analyzed both statistically and regarding mutations comprehensively. The distribution of clades and lineages in different cities of T & uuml;rkiye and the association of SARS-CoV-2 variants with age groups and clinical characteristics of COVID-19 were also examined. Furthermore, the frequency of the clades and lineages was observed in 10 months. Finally, non-synonymous mutations not defined in specific SARS-CoV-2 variants (during that period) were identified by performing mutation analysis. B.1.1.7 (Alpha) and B.1.617.2 (Delta) SARS-CoV-2 variants which have also been identified in our study from March to December 2021. We observed a significant association of SARS-CoV-2 variants with age groups and cities. Also, E:T9I, S:A27S, S:A67V, S:D796Y, S:K417N, S:N440K, S:R158X, S:S477N (below 1%-frequency) were determined as specific mutations belonging and shared with the Omicron variant that appeared later. Our study has highlighted the importance of constant monitoring of the genetic diversity of SARS-CoV-2 to provide better prevention strategies and it contributes to the understanding of SARS-CoV-2 from the past to the present.