California Gov. Gavin Newsom urged residents to heed health warnings during the holiday season as the state's hospital system is pushed to the limit with COVID-19 patients.

He warned there could be multiple surges in cases "unless we are cautious and mindful about our travel plans this holiday season and about our proximity to people outside our households."

The number of the Intensive Care Unit patients is now 3,827, which was nearly double the 2,006 patients on Dec. 1, according to Newsom.

"On Monday, we were at 2.5% ICU availability and now as a state today, we are down to 1.1% ICU bed availability," he said.

"We had 8,517 people that were in our hospitals that tested positive for COVID-19 on Dec. 1st. Now 18,828 people are testing positive in just a three-week period," Newsom added.

-ABC News' Cammeron Parish contributed to this report

The new COVID-19 variant in the United Kingdom has likely infected tens of thousands of people, Jeffrey Barrett, director of the COVID-19 Genomics Initiative at the U.K. Wellcome Sanger Institute, said at a virtual Q&A hosted by the World Health Organization.

While there are just over 3,000 people who have the full genome sequence confirmed for the variant, only a small fraction of cases are sequenced, he said.

There’s no evidence the new variant is more deadly and it’s highly likely the vaccine will still work, officials said.

ABC News’ Sony Salzman contributed to this report.

Thursday, Dec. 24, Dr. Anthony Fauci’s 80th birthday, will be "Dr. Anthony S. Fauci" day in Washington, D.C., Mayor Muriel Bowser announced Wednesday.

"We are incredibly proud to count Dr. Fauci among the many DC residents who are sacrificing so much to keep our communities healthy and safe,” Bowser tweeted.

Hard-hit California reported 39,069 daily cases on Wednesday -- a 2% increase from Tuesday.

California’s daily cases are more than the daily cases in the United Kingdom, Russia, India, Italy and France, according to Johns Hopkins University data.

California is recording more than twice as many daily cases than the next hardest-hit states. Tennessee recorded 16,036 cases Tuesday and Texas had 16,607 cases, according to Johns Hopkins.

ABC News’ Bonnie Mclean contributed to this report.

The Duke women's basketball team has decided to end its season due to the coronavirus pandemic.

"The student-athletes on the Duke women's basketball team have made the difficult decision to conclude their current season due to safety concerns," Michael Schoenfeld, Duke's vice president for public affairs and government relations and chief communications officer, said in a statement. "We support their decision, as we have supported the choices made by all student-athletes at Duke during this unprecedented time."

The team suspended activities on Dec. 16 after two members of the program's "travel party" tested positive for COVID-19. It's unclear if they were players or staff, but contact tracing didn't allow for the team to field enough players.

The Blue Devils had gone 3-1 in the first four games under newly hired head coach Kara Lawson. The former Tennessee star and ESPN commentator said earlier this season she did not believe that college basketball games should proceed during the pandemic.

Duke men's coach, Hall of Famer Mike Krzyzewski, made similar comments this month as well. The men's team, currently ranked No. 20 in the AP poll, has continued to play.

The Duke women's team is the first major program to end their season.