Detection of a cluster of Omicron's BA.4 sublineage in Northern Senegal and identification of the first XAS recombinant variant in Senegal.

• Identification of the first recombinant XAS sequence reported from Senegal. • Characterization of the origin of cluster of infections with the BA.4 sublineage. • Rapid expansion and sustained local transmission of the BA.4 sublineage in Senegal. In Senegal, since its first detection in early March 2020, genomic surveillance of SARS-CoV-2 isolates has led to the identification of the emergence of the Omicron BA.4 and BA.5 sublineages from early June 2022. To investigate the origin of a cluster of cases in Northern Senegal on July 2022, isolates were analysed using Next-generation sequencing and phylogeny. Our data provided evidence of the origin of the cluster of BA.4 cases from a XAS recombinant, that is to date, the first reported sequence of this variant from Senegal. Continuous genomic surveillance of positive SARS-CoV-2 samples is a crucial need. [ABSTRACT FROM AUTHOR]