Since the beginning of the COVID-19 pandemic, the SARS-CoV-2 virus has undergone various genetic mutations which have led to the emergence of variants. The World Health Organization (WHO) defines Variants of Concern (VOCs) and Variants of Interest (VOIs) according to several criteria. These include significant changes in the transmissibility and pathogenicity of the virus characterized by mutations in the spike gene coding the spike glycoprotein. In this study, we designed ten Reverse-Transcriptase Polymerase Chain Reaction (RT-PCR) assays in order to identify mutations of SARS-CoV-2 in overlapping fragments. Each assay contained mutations on the fragments sequenced by a Sanger method. The genomic analysis of the fragments allowed to identify the variant according to the position of the mutations. The assembly of the 10 fragments refined the analysis, highlighting all the mutations present in the S gene. Finally, a comparison of methods using a Next-Generation Sequencing (NGS) approches for samples enabled the method to be validated. By this method we have highlighted a characteristic mutation of the lineage B of SARS-CoV-2. We showed the circulation of SARS-CoV-2 belonging to lineage A and B in the beginning of the pandemic in Gabon. We have identified the Alpha, Delta and Omicron variants. This method would allow laboratories with limited financial means or without NGS instrument to obtain sequences of the S gene. This method wase very effective to highlight the circulation of variants, in particular VOCs and VOIs, in this developing country, Gabon, during the COVID-19 pandemic.

SARS-CoV-2, the causative agent of COVID-19, emerged in late 2019 and rapidly developed into a global health crisis. In this study, we analysed 173,194 SARS-CoV-2 genomes from the GISAID database to explore the intra-continental dynamics and distribution of variants across Africa between 2020 and 2024. We have identified 1377 distinct lineages, which were classified by clade to assess associations with infection and mortality rate. So, we conducted a Shannon entropy analysis to confirm the diversity and we applied a Correspondence Analysis (CA). Our findings revealed that one of the deadliest in Africa during the Delta wave, lineage AY.45 predominated in the South Africa cluster, whereas AY.34.1 drove transmission in the Atlantic West Africa cluster, underscoring regional heterogeneity. Furthermore, early in the pandemic, men exhibited a 39% higher risk of infection compared to women (aOR: 1.39, 95% CI [1.34–1.45]), particularly in association with clade G. By contrast, later stages were dominated by clade GRA, which disproportionately affected the elderly (≥70 years; aOR: 1.39, 95% CI [1.33–1.45]) and children (0–9 years; aOR: 1.26, 95% CI [1.20–1.33]). Our analysis highlighted that the pandemic on the African continent unfolded as a mosaic of epidemics shaped by diverse variants and regional epidemiological contexts. These findings emphasize the importance of genomic surveillance to capture local epidemic signatures and inform region-specific public health strategies.