The rapidly spreading variant now appears to be responsible for nearly three quarters of new infections nationwide.
Less than three weeks after the Omicron variant was first identified in the United States, it's already the dominant variant in the country.
The Omicron variant accounts for 73% of new infections between Dec. 12-18, according to the U.S. Centers for Disease Control and Prevention. The CDC confirmed the first case in the U.S. on Dec. 1.
Now, the Omicron appears to be fueling a surge in cases nationwide.
In parts of the East Coast and the Pacific Northwest, the CDC projects Omicron accounts for more than 90% of new infections over the past week.
Nationwide, more than 133,000 new cases are being reported per day, up from about 90,000 a month ago, according to The New York Times daily tracker. About 69,000 COVID-19 patients are being treated in hospitals, a 16% increase over the past 14 days, The Times reports.
Healthcare leaders have said they are worried about the rapidly spreading variant adding more stress to an already strained hospital system.
Hospital systems across the country have already begun postponing non-urgent surgeries over the past few weeks due to the rise in cases and hospitalizations. States such as New York, Massachusetts and Maryland have ordered at least some hospitals to delay non-urgent procedures.
In some midwestern states like Minnesota and Ohio, health leaders have said the wave is more challenging than the peak seen last winter. In addition to treating many COVID-19 patients, many health systems say they're battling staff shortages, as some nurses and other clinical workers have left their jobs.
Many hospitals are also seeing patients with other health issues, including the flu and respiratory viruses. They're also seeing more patients who deferred care for some other health issues and now are showing up in hospitals needing treatment.
Health system leaders said they're worried about the prospect of more infections and hospitalizations as Americans travel for the holidays.
In the last week, hospitals systems in both Ohio and Minnesota published joint advertisements in local newspapers urging people to get vaccinated. Most of an ad appearing in the Cleveland Plain Dealer is dominated by one word: "Help." The ad concludes, "We need you to care as much as we do." The Minnesota ad was headlined, "We're heartbroken. We're overwhelmed."
In an appearance on CNN's "State of the Union" Sunday, Dr. Anthony Fauci, the federal government's leading expert on infectious diseases, said the Omicron variant is "going to take over."
A day later, the CDC affirmed the projection was correct.