Temporal Dynamics and Genomic Landscape of SARS-CoV-2 After Four Years of Evolution.

Introduction Since its emergence, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has undergone extensive genomic evolution, impacting public health policies, diagnosis, medication, and vaccine development. This study leverages advanced bioinformatics to assess the virus's temporal and regional genomic evolution from December 2019 to October 2023. Methods Our analysis incorporates 16,575 complete SARS-CoV-2 sequences collected from 214 countries. These samples were comparatively analyzed, with a detailed characterization of nucleic mutations, lineages, distribution, and evolutionary patterns during each year, using the Wuhan-Hu-1 strain as the reference. Results Our analysis has identified a total of 21,580 mutations that we classified into transient mutations, which diminished over time, and persistent mutations with steadily increasing frequencies. This mutation landscape led to a notable surge in the evolutionary rate, rising from 13 mutations per sample in 2020 to 96 by 2023, with minor geographic variations. The phylogenetic analysis unveiled three distinct evolutionary branches, each representing unique viral evolution pathways. These lineages exhibited a tendency for a reduced duration of dominance with a shortening prevalence period over time, as dominant strains were consistently replaced by more fit variants. Notably, the emergence of the Alpha and Delta variants in 2021 was followed by the subsequent dominance of Omicron clade variants that have branched into several recombinant variants in 2022, marking a significant shift in the viral landscape. Conclusion This study sheds light on the dynamic nature of SARS-CoV-2 evolution, emphasizing the importance of continuous and vigilant genomic surveillance. The dominance of recombinant lineages, coupled with the disappearance of local variants, underscores the virus's adaptability.

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance.

Investment in Africa over the past year with regards to SARS-CoV-2 genotyping has led to a massive increase in the number of sequences, exceeding 100,000 genomes generated to track the pandemic on the continent. Our results show an increase in the number of African countries able to sequence within their own borders, coupled with a decrease in sequencing turnaround time. Findings from this genomic surveillance underscores the heterogeneous nature of the pandemic but we observe repeated dissemination of SARS-CoV-2 variants within the continent. Sustained investment for genomic surveillance in Africa is needed as the virus continues to evolve, particularly in the low vaccination landscape. These investments are very crucial for preparedness and response for future pathogen outbreaks. One-Sentence SummaryExpanding Africa SARS-CoV-2 sequencing capacity in a fast evolving pandemic.

A year of genomic surveillance reveals how the SARS-CoV-2 pandemic unfolded in Africa

The progression of the SARS-CoV-2 pandemic in Africa has so far been heterogeneous and the full impact is not yet well understood. Here, we describe the genomic epidemiology using a dataset of 8746 genomes from 33 African countries and two overseas territories. We show that the epidemics in most countries were initiated by importations, predominantly from Europe, which diminished following the early introduction of international travel restrictions. As the pandemic progressed, ongoing transmission in many countries and increasing mobility led to the emergence and spread within the continent of many variants of concern and interest, such as B.1.351, B.1.525, A.23.1 and C.1.1. Although distorted by low sampling numbers and blind-spots, the findings highlight that Africa must not be left behind in the global pandemic response, otherwise it could become a breeding ground for new variants.

Genetic analysis of SARS-CoV-2 strains collected from North Africa: viral origins and mutational spectrum

The SARS-CoV-2 identified as coronavirus species associated with severe acute respiratory syndrome. At the time of writing, the genetic diversity of Moroccan strains of SARS-CoV-2 is poorly documented. The present study aims to analyze and identify the genetic variants of fortyeight Moroccan strains of SARS-CoV-2 collected from mid-March to the end of May and the prediction of their possible sources. Our results revealed 108 mutations in Moroccan SARS-CoV-2, 50% were non-synonymous were present in seven genes (S, M, N, E, ORF1ab, ORF3a, and ORF8) with variable frequencies. Remarkably, eight non-synonymous mutations were predicted to have a deleterious effect for (ORF1ab, ORF3a, and the N protein. The analysis of the haplotype network of Moroccan strains suggests different sources of SARS-CoV-2 infection in Morocco. Likewise, the phylogenetic analysis revealed that these Moroccan strains were closely related to those belonging to the five continents, indicating no specific strain dominating in Morocco. These findings have the potential to lead to new comprehensive investigations combining genomic data, epidemiological information, and clinical characteristics of SARS-CoV-2 patients in Morocco and could indicate that the developed vaccines are likely to be effective against Moroccan strains.

Genomic diversity and hotspot mutations in 30,983 SARS-CoV-2 genomes: moving toward a universal vaccine for the "confined virus"?

The COVID-19 pandemic has been ongoing since its onset in late November 2019 in Wuhan, China. Understanding and monitoring the genetic evolution of the virus, its geographical characteristics, and its stability are particularly important for controlling the spread of the disease and especially for the development of a universal vaccine covering all circulating strains. From this perspective, we analyzed 30,983 complete SARS-CoV-2 genomes from 79 countries located in the six continents and collected from December 24, 2019, to May 13, 2020, according to the GISAID database. Our analysis revealed the presence of 3,206 variant sites, with a uniform distribution of mutation types in different geographic areas. Remarkably, a low frequency of recurrent mutations has been observed; only 169 mutations (5.27%) had a prevalence greater than 1% of genomes. Nevertheless, fourteen non-synonymous hotspot mutations (> 10%) have been identified at different locations along the viral genome; eight in ORF1ab polyprotein (in nsp2, nsp3, transmembrane domain, RdRp, helicase, exonuclease, and endoribonuclease), three in nucleocapsid protein and one in each of three proteins: spike, ORF3a, and ORF8. Moreover, 36 non-synonymous mutations were identified in the RBD of the spike protein with a low prevalence (<1%) across all genomes, of which only four could potentially enhance the binding of the SARS-CoV-2 spike protein to the human ACE2 receptor. These results along with mutational frequency dissimilarity and intra-genomic divergence of SARS-CoV-2 could indicate that the SARS-CoV-2 is not yet adapted to its host. Unlike the influenza virus or HIV viruses, the low mutation rate of SARS-CoV-2 makes the development of an effective global vaccine very likely.