Genome characterization of the SARS-CoV-2 omicron in Cameroon

The omicron lineage has been declared the fifth variant of concern (VOC) by the World Health Organization (WHO). This study aims to describe the genomic characteristics of omicron sequences from Cameroon and to discuss the potential implications of identified mutations for viral evolution and immune escape, based on existing literature. This study is a retrospective analysis of publicly available SARS-CoV-2 sequences from Cameroon submitted to GISAID (Global Initiative on Sharing Avian Influenza Data). Full-length omicron sequences from across Cameroon were retrieved from the GISAID database. Phylogenetic analyses were conducted using Nextstrain SARS-CoV-2 Workflow version 8.2.0, and mutation analysis was performed using the Nextstrain web tool, with the Wuhan-Hu-1/2019 strain as a reference. A total of 1,428 omicron sequences were analyzed, revealing eleven variants: BA.1 lineage (45.0%), B.1.1.529 (0.2%), BA.2 (7.7%), BA.4 (6.5%), BA.5 (16.3%), BE (12.2%), BF (6.3%), BN.2 (0.1%), BQ.1 (3.7%), XBB (0.5%) and JN.1 (1.5%). The sequences exhibited high number of mutations in the spike gene, with the JN.1 lineage showing the highest mutation count. All lineages contained mutations associated with neutralizing antibody evasion, including R346T, K417N, G446S, E484A, or Q493R. Ongoing monitoring of omicron lineages is crucial to detect emerging variants and adapt vaccine strategies. The significant mutations, particularly in the JN.1 lineage warrant further investigation to assess their potential impact on transmissibility or immune escape. Not applicable.