Omicron already dominant COVID-19 variant in US: CDC

Just three weeks after it was first discovered in the United States, the U.S. Centers for Disease Control and Prevention now estimates that the highly transmissible omicron variant is the dominant variant in the United States, representing 73% of new coronavirus cases, as of Dec. 18.

The variant has now been detected in all but two states -- Oklahoma and North Dakota. In some parts of the country -- including the New York, New Jersey area, much of the South, the upper Midwest, and the Pacific Northwest, the omicron variant now accounts for more than 90% of new cases.

The significant increase is 70% higher than just two weeks ago, when omicron, also known as B.1.1.529, was estimated to account for just 0.4% of all new cases.

"This sharp rise in omicron was expected and is similar to what has been seen worldwide," the CDC said in a statement Monday. "We know layered prevention strategies can slow the spread of COVID-19."

The World Health Organization and the CDC have both identified omicron as a variant of concern.

Health officials and experts alike have warned that the omicron variant is a more infectious version of the disease, and is likely to cause a significant COVID-19 surge in the weeks and months to come.

“This virus is extraordinary. It has a doubling time of anywhere from two to three days,” Dr. Anthony Fauci, chief medical adviser to the White House, said on Sunday during an appearance on CNN’s State of the Union.

The country's latest COVID-19 resurgence comes just a week before Christmas and the New Year, as millions of Americans are set to gather and travel for the holidays.

The U.S. is currently averaging more than 130,000 new cases a day, more than double the average from two months ago. Nationwide, nearly 70,000 Americans are currently hospitalized with COVID-19, and just under 1,200 Americans are still being reported lost to the virus every day.

Health officials continue to urge the public to get vaccinated and boosted as soon as possible, given concerns over waning immunity.

Early data from Moderna on Monday found that its current vaccine booster candidate increases antibody levels against omicron 37-fold. Earlier this month, Pfizer reported that its booster increased antibody levels 25-fold.