A health worker takes a swab sample from a man for COVID-19 test in the Brooklyn borough of New York, the United States, Dec. 17, 2021. (Photo by Michael Nagle/Xinhua)

Omicron has become the dominant COVID-19 variant in the United States, accounting for over 73 percent of new weekly cases, according to the latest model estimates of the Centers for Disease Control and Prevention (CDC) on Monday.

The infection cases caused by the Omicron variant jumped from 12.6 percent of all infection cases in the week ending Dec. 11 to 73.2 percent in the week ending Dec. 18, CDC data showed.

In the week ending Dec. 4, Omicron only accounted for 0.7 percent of all infection cases.

The Omicron variant is spreading rapidly nationwide and has been found in at least 48 U.S. states as of Monday, since the first case in the country was detected in California on Dec. 1.