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

Automated summary

Genomic surveillance in Senegal since March 2020 has detected the emergence of Omicron BA.4 and BA.5 sublineages in June 2022. Next-generation sequencing and phylogeny analysis of isolates from a cluster of cases in Northern Senegal in July 2022 revealed that the BA.4 cases originated from a XAS recombinant, marking the first reported sequence of this variant from Senegal. Continuous genomic surveillance of positive SARS-CoV-2 samples is crucial.