(CNN) President Joe Biden on Wednesday had a sharp response to a reporter's question on a report that suggested then-President Donald Trump tested positive for Covid-19 last year earlier than previously disclosed.
Trump tested positive for Covid-19 three days ahead of his first 2020 presidential debate with Biden -- though he also had a negative result in that same timeframe, according to excerpts from a forthcoming book from the former Republican President's chief of staff, Mark Meadows, reported by The Guardian.
Asked whether he felt Trump put him at risk when the two appeared on stage together at a September 2020 debate in Ohio, Biden said, "I don't think about the former President," before leaving the room.
Later Wednesday afternoon at the White House press briefing, National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci told reporters he was not aware that Trump had tested positive for ahead of the debate.
"I certainly was not aware of his test positivity or negativity," Fauci said.
Pressed on whether Trump had put Biden at risk for contracting Covid-19, Fauci said, "I'm not going to specifically talk about who put who at risk. But I would say, as I've said, not only for an individual but for everybody, that if you test positive, you should be quarantining yourself."
White House press secretary Jen Psaki also said during the briefing that before the release of the book excerpt, Biden and his aides were not aware of Trump's early positive Covid-19 test.
"I think for people who were watching at home, obviously this debate occurred more than a year ago, and as you know, the President is very healthy, as you saw in the release of his medical report from last week, and he is tested regularly," Psaki said, pointing to Biden's negative Covid-19 test Monday.
Psaki also criticized Trump, who she said "withheld information reportedly about testing positive, and appeared apparently at a debate -- also held events of the White House, reportedly with military veterans and military families."
Trump received the positive test on September 26, 2020, according to Meadows, The Guardian reported. That day Trump hosted a ceremony in the White House Rose Garden for then-Supreme Court nominee Amy Coney Barrett, which was later deemed a super spreader event, by medical experts. At least 12 people who attended the event later tested positive.
Trump, who Meadows said looked "a little tired," was en route to a rally in Middletown, Pennsylvania, that night when Meadows received a call from then-White House physician Dr. Sean Conley informing him that Trump had tested positive, according to the excerpt. Meadows wrote that Conley told him, "Stop the President from leaving. He just tested positive for Covid."
Meadows claims in his book, "The Chief's Chief," that the positive test was done with an old-model kit, The Guardian reported.
Trump was subsequently tested with "the Binax system," an antigen test for Covid-19, and returned a negative result, Meadows wrote. It is unclear if the first test, which returned the positive result, was an antigen test or PCR test.
Meadows wrote that Trump took the negative test as "full permission to press on as if nothing had happened," but Meadows instructed those in Trump's "immediate circle to treat him as if he was positive," The Guardian reports.
Trump said in a statement Wednesday, "The story of me having COVID prior to, or during, the first debate is Fake News. In fact, a test revealed that I did not have COVID prior to the debate."
During the debate, both presidential candidates adhered to certain Covid-19 protocols, including forgoing handshakes and, while unmasked, remaining socially distanced.
Trump mocked Biden for frequently wearing a mask, saying during the debate, "He could be speaking 200 feet away from them and he shows up with the biggest mask I've ever seen."
The incumbent also suggested onstage that Covid-19 testing made it possible for him to hold major campaign rallies.
"I put a mask on when I think I need it. Tonight, as an example, everybody's had a test and you've had social distancing and all of the things that you have to, but I wear masks when needed," he said.
Between the first positive Covid-19 test ahead of the presidential debate and the White House's public disclosure that Trump tested positive on October 1, Trump continued to mingle, often unmasked, with government officials and the public.
He golfed, did debate prep sessions with his team, visited a golf course, traveled to New Jersey and Minnesota, attended political fundraisers, held a political rally, held a news conference and hosted several White House events, including a reception for Gold Star families.
Trump was hospitalized for his Covid-19 symptoms at Walter Reed National Military Medical Center from October 2 through October 5, 2020.
During a news conference on October 3, 2020, as Trump was receiving treatment at Walter Reed, Conley would not disclose Trump's last negative test for the virus, saying, "I'm not going to get into all the testing going back, but he and all his staff routinely are tested."
Later that October, Trump did not definitively say whether he had been tested on the day of his first presidential debate.
"I don't know, I don't even remember," Trump said, when asked during a NBC News town hall if a test had been done on the day of the September 29 debate.
Asked again whether he had had a test in adherence to rules set by the Commission on Presidential Debates, Trump said at the town hall: "I probably did, and I took a test the day before."
Asked once more, he said: "Possibly I did, possibly I didn't."
The President also said he could not recall the last time he had tested negative for coronavirus before testing positive in early October.
CNN has reached out to Meadows and Conley for comment.
This story has been updated with additional information.
CORRECTION: A previous version of this story misstated when the first 2020 presidential debate took place. It was in September 2020.