Genomic Surveillance Reveals The Rapid Expansion Of The XBB Lineage Among Circulating SARS-CoV-2 Omicron Lineages In Southeastern Wisconsin, USA

The study conducted genomic surveillance of SARS-CoV-2 in Southeastern Wisconsin, focusing on the period from November 2021 to April 2023, to understand the spread and characteristics of the virus, particularly the XBB lineage. By analyzing 6,709 sequences alongside 1,520 from other labs, researchers found that 88.8% of the virus belonged to the Omicron variant, with dominant sublineages XBB.1.5, XBB.1.16, and XBB.1.9.1. These sublineages exhibited mutations in the Spike protein, enhancing viral reproduction, transmission, and immune evasion. The study identified 38 prevalent mutations in XBB.1.5, with significant transmission occurring within households and counties. The findings aided public health agencies in implementing strategies to mitigate COVID-19 spread and monitor emerging variants' impacts on diagnostics, treatments, and vaccines.