WASHINGTON — Vice President Kamala Harris tested positive for COVID-19 on Tuesday after returning from a weeklong trip to California.

"Today I tested positive for COVID-19. I have no symptoms, and I will continue to isolate and follow CDC guidelines. I'm grateful to be both vaccinated and boosted," Harris tweeted Tuesday afternoon.

Kirsten Allen, the vice president's press secretary, said in an earlier statement that Harris tested positive for COVID-19 on rapid and PCR tests. Harris "will isolate and continue to work from the vice president's residence," Allen said.

"She has not been a close contact to the President or First Lady due to their respective recent travel schedules. She will follow CDC guidelines and the advice of her physicians. The Vice President will return to the White House when she tests negative," she added.

Harris had been scheduled to receive her intelligence briefing at 10:15 a.m. ET Tuesday at the White House alongside President Joe Biden, according to daily guidance sent to reporters Monday evening. She did not participate in any events or meetings at the White House on Tuesday, according to a White House official.

White House COVID-19 response coordinator Dr. Ashish Jha said he did not know if Harris is being treated with therapeutics. "That's a conversation that she's having with her physician. I'm not her physician. I'm not privy to those conversations, so I don't know the answer to that," he said.

Contact tracing is under way, a White House official said. Officials will notify the appropriate people, but as of Tuesday afternoon, the office had not identified close contacts among staff.

A handful of staff members traveled with Harris to California last week, including deputy chief of staff Mike Fuchs and national security adviser Phil Gordon. It's unclear whether all staff members listed stayed in California with Harris through the duration of her weeklong trip.

Biden and Harris spoke over the phone on Tuesday afternoon, according to the White House. "He wanted to check in and make sure she has everything she needs as she quarantines at home," a White House statement to reporters said.

The President last tested negative for COVID-19 on Monday, White House press secretary Jen Psaki said.

Harris' isolation will have immediate impact on Senate Democrats. Democratic Sens. Chris Murphy of Connecticut and Ron Wyden of Oregon both also announced they had tested positive as well on Tuesday, meaning that their absences — along with Harris — will delay Democrats' plans to confirm a pair of high-profile nominees this week, a senior Democratic aide told CNN.

Senate Majority Leader Chuck Schumer hoped to confirm Lisa Cook to be a member of the Federal Reserve Board and Alvaro Bedoya to be the chair of the Federal Trade Commission.

But because there is broad Republican opposition to them, votes to process those nominations will be put off until Democrats, who narrowly control the 50-50 chamber, are back to full strength.

In a sign of the partisan combativeness that is so prevalent in the Senate, Republicans will still force a procedural roll call vote on Cook's nomination — which will fail — later Tuesday and force Democrats to go through the process of breaking a filibuster against her again.

GOP senators could have given consent to waive the actual vote but didn't. Republicans have not said yet if they would do the same with Bedoya's nomination.

"That is something that members and leaders will work through in Congress," Psaki told reporters on Tuesday when asked about the dilemma. "We are confident we have the votes to get them confirmed. We're eager to have them in place. But of course, we need all the people, all members there to do that."

The Senate confirmed Lael Brainard to be the vice chair of the Fed Tuesday afternoon. Her nomination is not affected by the absences because she has bipartisan support. — CNN