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 Türkiye 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.