The U.S. Centers for Disease Control and Prevention (CDC) is continuing to use its genomic surveillance system to monitor COVID-19 variant levels and treatments throughout the U.S.
The system tracks proportions of genetic sequence variations in COVID-19 from the national to jurisdictional level, which then informs whether the COVID-19 tests, treatments and vaccines authorized or approved for use in the U.S. will work against emerging variants.
The estimates produced by this surveillance system are used to track the most common COVID-19 variants in any given timeframe or region. The newest omicron subvariant, XBB. 1.5, is on the rise across the country, accounting for 40% of U.S. COVID-19 cases and 75% of cases in the Northeast. Prior to the rise of XBB. 1.5, BA.5, another omicron subvariant, was responsible for most COVID-19 cases in the U.S. beginning in December 2022.
Updated variant proportion data, which is updated each Friday by the CDC, can be found here.