President Joe Biden has tested positive for Covid-19, the White House said Thursday.

The 79-year-old president, who is fully vaccinated and has received two Covid booster shots, is experiencing “very mild symptoms,” press secretary Karine Jean-Pierre said in a statement. Biden previously tested negative on Tuesday.

Biden has begun taking Paxlovid, an antiviral pill that can reduce the risk of hospitalization for people who test positive for Covid, the press secretary said.

The president’s symptoms include a dry cough, runny nose and fatigue, White House physician Kevin O’Connor said in a memorandum. Those symptoms began Wednesday evening, O’Connor said.

“I anticipate that he will respond favorably, as most maximally protected patients do,” the physician added.

First lady Jill Biden told reporters in Detroit on Thursday morning that her husband is “feeling good.”

“I talked to him just a few minutes ago, he’s doing fine,” Jill Biden said. She is considered a close contact to the president, but tested negative for Covid on Thursday and is following CDC social distancing guidelines, her office said.

Biden will work in isolation until he tests negative for the virus, Jean-Pierre said. He will hold all of his planned meetings remotely Thursday.

Jean-Pierre will hold a press briefing at 2 p.m. ET, accompanied by White House Covid response coordinator, Dr. Ashish Jha.

Biden attended an event in Massachusetts on Wednesday to announce policies to fight climate change. Lawmakers and administration officials in attendance included Sens. Elizabeth Warren and Ed Markey, D-Mass., climate envoy John Kerry and climate advisor Gina McCarthy.

It was unclear if any of those officials are considered close contacts with Biden under CDC guidelines.

At the time of the White House’s announcement, Vice President Kamala Harris, 57, was flying on Air Force Two to Charlotte, North Carolina, where she was scheduled to discuss the Biden administration’s investments in high-speed internet and meet with state leaders, her office told NBC. No decision yet has been made to change her schedule, NBC reported.

The first lady said she planned to keep her schedule in Detroit, where she was set to visit public schools and discuss how federal funds are being used to address students’ mental health issues and Covid-related learning disruptions.

The White House’s handling of Biden’s Covid diagnosis so far stands in stark contrast to the way former President Donald Trump’s administration revealed his positive test to the public.

Trump himself announced in an Oct. 2, 2020, tweet that he and then-first lady Melania Trump tested positive for Covid. That evening, Trump was airlifted to Walter Reed Medical Center in what the White House at the time called a “precautionary measure.” At that time, Covid vaccines were not widely available.

A year later, former White House chief of staff Mark Meadows revealed in a book that Trump had received a positive test on Sept. 26, three days before he debated Biden in person without a mask. Trump subsequently took a negative test hours after the initial one.

Trump’s doctor confirmed that the president received supplemental oxygen twice while hospitalized. He had also taken doses of the antiviral therapy remdesivir.

Read the full statement from the White House:

This morning, President Biden tested positive for COVID-19.  He is fully vaccinated and twice boosted and experiencing very mild symptoms.  He has begun taking Paxlovid. Consistent with CDC guidelines, he will isolate at the White House and will continue to carry out all of his duties fully during that time.  He has been in contact with members of the White House staff by phone this morning, and will participate in his planned meetings at the White House this morning via phone and Zoom from the residence.

Consistent with White House protocol for positive COVID cases, which goes above and beyond CDC guidance, he will continue to work in isolation until he tests negative.  Once he tests negative, he will return to in-person work.

Out of an abundance of transparency, the White House will provide a daily update on the President’s status as he continues to carry out the full duties of the office while in isolation.

Per standard protocol for any positive case at the White House, the White House Medical Unit will inform all close contacts of the President during the day today, including any Members of Congress and any members of the press who interacted with the President during yesterday’s travel.  The President’s last previous test for COVID was Tuesday, when he had a negative test result.