Coronavirus updates: US reports nearly 300,000 new cases in all-time high

A man in his 20s in Colorado is confirmed to have the COVID-19 variant that was detected in the United Kingdom, Colorado officials said.

This is believed to be the first known case of the variant in the U.S.

The man, who’s had no travel history, is in isolation, officials said.

“Public health officials are doing a thorough investigation,” Colorado officials said. “The individual has no close contacts identified so far, but public health officials are working to identify other potential cases and contacts through thorough contact tracing interviews.”

The variants are all the same virus, no matter their small genetic differences. SARS-COV-2 is a respiratory virus, meaning it is transmitted through droplets, so masks and social distancing still work to slow transmission, no matter the variant.

Colorado Gov. Jared Polis reiterated that health officials will monitor the case closely.

"We are working to prevent the spread and contain the virus at all levels," he said in a statement.

Stay-at-home orders are extended in California’s hard-hit Southern California and the state's San Joaquin region, where ICU capacities remain at 0%.

Hospitalizations in the Golden State have increased 36.5% over the last two weeks; now 20,390 coronavirus patients are in hospitals.

ICU hospitalizations have increased 35.1% over last two weeks and now stand at 4,308 patients. 

Dr. Mark Ghaly, Secretary of California Health and Human Services, on Tuesday outlined plans for hospitals’ “crisis care” mode, which is when care for patients would have to be rationed. California is not there yet, he said, adding that it’s important to prepare.

"We certainly know SoCal hospitals are in crisis,” Ghaly said.

“Some hospitals in SoCal have put in place some practices that would be part of crisis care, whether it’s decisions about how ambulances are received or how stretched staff become,” Ghaly said. “But we have not heard of a hospital needing to make a decision between two patients who need ventilators and needed to make a decision between them or any care decisions like that.”

ICU capacity in California’s three other regions stand at: 10.4% in the Bay Area, 19.1% in Greater Sacramento and 27.9% in Northern California. All regions but Northern California are under stay-at-home orders.

ABC News’ Alyssa Pone, Alex Stone and Michelle Mendez contributed to this report.

Margaret Keenan, the 91-year-old grandmother in the United Kingdom who was the first in the world (outside of clinical trials) to get the Pfizer vaccine, got her second dose on Tuesday.

Keenan, then 90, received her first dose on Dec. 8.

ABC News’ Rashid Haddou contributed to this report.

Dr. Anthony Fauci says the pandemic has “gotten out of control” and warned that January may be worse than December.

“That is what we're concerned about,” Fauci told CNN. “That in addition to the surge, we're going to have an increase … which could make January even worse than December. I hope not, I hope that doesn't happen, but it certainly is possible.” 

“I think we just have to assume that it’s gonna get worse,” he said.

In terms of vaccines administered so far, Fauci said, “We certainly are not at the numbers that we wanted to be at the end of December.”

Over 11.4 million vaccine doses have been distributed and 2,127,143 Americans have received their first vaccine dose, according to the CDC.

Fauci said he believes there’ll be “an increase in the momentum” of vaccinations in January.

“Not being responsible myself for the rollout, I can't personally guarantee that we’re gonna catch up,” Fauci said. “I hope we do.” 

Assistant Secretary for Health Adm. Brett Giroir said the data on people vaccinated is delayed.

“We know that’s underreported because there’s a three to seven-day delay. But we expect that to ramp up,” Giroir told MSNBC Tuesday..

ABC News’ Brian Hartman contributed to this report.