Omicron now 95% of new COVID-19 infections in U.S., CDC estimates

The Omicron variant made up around 95.4% of new COVID-19 cases in the U.S. last week, the Centers for Disease Control and Prevention said in an updated estimate published on Tuesday. Only two regions of the U.S. — New England and part of the Midwest — have yet to reach 90% locally. The Delta variant, which was dominant up until a few weeks ago, makes up nearly all the other cases.

Earlier federal estimates showed Omicron rapidly spreading, but with labs in several states still working on sequencing their first outbreaks of the variant, the precise numbers were hard to pin down.

However, in the weeks since, CDC officials have said the agency has worked to refine its projections of the variant's growth as more labs have sequenced Omicron cases. The CDC collects data from commercial and local public health laboratories, as well as from its own contractors, to track variants in the country and produce its "Nowcast" estimates.