The Omicron variant accounted for 22.5% of recent COVID-19 cases in the U.S. on the week that ended on Dec. 18 , according to the Centers for Disease Control and Prevention's updated estimate released on Dec. 28.

The latest: The revised data shows Omicron's share of COVID-19 infections nearly tripled in just one week.

• The variant was only detected in the U.S. a few weeks ago. Still, the strain has spread rapidly throughout the country and threatens to overturn the new normal.

What they're saying: "These numbers are stark, but they're not surprising," said Rochelle Walensky, the CDC's director, adding that the growing infections reflect what has been seen in other countries.

• While the Delta variant still drives up a lot of new infections, Walensky told AP she anticipates "that over time that Delta will be crowded out by Omicron."

What's next: President Biden on Tuesday will deliver a speech outlining new steps the administration will take to address the rapid spread of the new variant.

Go deeper: Why the CDC slashed its first estimate of Omicron case prevalence

Editor's note: The headline and story was updated after the CDC revised its estimates of Omicron prevalence in new COVID cases in the U.S., to 23% from 73% for the week ending Dec. 18.