(WASHINGTON) — President Joe Biden on Wednesday declined to comment on the claim former President Donald Trump’s chief of staff Mark Meadows makes in an upcoming book, according to the Guardian, that Trump had a positive COVID-19 test three days before their first presidential debate.

ABC News Senior White House Correspondent Mary Bruce asked Biden, who was 78 and, like Trump, unvaccinated when they shared the stage in the September debate, if he believes Trump put him at risk of contracting the potentially fatal virus.

Biden paused, and then responded with a smirk, “I don’t think about the former president.”

Later, White House press secretary Jen Psaki took a different tone — slamming Republicans and Trump allies she said had appeared to withhold the positive test result.

“What is not lost on us is that no one should be surprised that currently in Congress, as we’re looking at the government staying open, you have supporters of the former president, supporters of the former president who withheld information, reportedly, about testing positive and appeared apparently at a debate, also held events at the White House, reportedly, with military veterans and military families,” she said.

She said the White House did not know about Meadows’ claim prior to the story breaking in The Guardian.

The nation’s top infectious disease expert, Dr. Anthony Fauci, who notably was the target of Trump’s ire for his messaging surrounding the virus, also said he “certainly was not aware of his test positivity or negativity” when ABC News Correspondent Karen Travers asked him about the revelation at the afternoon White House briefing.

“I’m not going to specifically talk about who put who at risk, but I would say, as I’ve said, not only from an individual but for everybody, that if you test positive, you should be quarantining yourself,” he said.

The Guardian , which says it obtained a copy of Meadows’ upcoming book, reported that Trump test positive on Sept. 26, sending shockwaves through the White House, before a second COVID-19 test came back negative, according to the Meadows account.

ABC News has not independently confirmed the book’s contents.

According to the debate rules, each candidate was required “to test negative for the virus within seventy-two hours of the start time” of the Sept. 29 debate in Cleveland, Meadows recalls understanding in the book, according to The Guardian.

But Trump, then 74, was determined to go to the debate and face Biden, regardless, according to the account.

“Nothing was going to stop [Trump] from going out there,” Meadows writes, according to the excerpt in The Guardian.

Trump’s reportedly positive, then negative, in tests were taken on the same day of the now-infamous packed Rose Garden ceremony, described as a “superspreader event,” in which Trump announced he would nominate now-Justice Amy Coney Barrett to the Supreme Court.

At least 11 guests, including press secretary Kellyanne Conway, former New Jersey GOP Gov. Chris Christie, Republican Sens. Mike Lee of Utah and Thom Tillis of North Carolina, and University of Notre Dame President John Jenkins, tested positive afterward.

Meadows called Trump, who was on Air Force One at the time, with news of the positive test before calling back that he tested negative after another screening.

Trump went on to headline a rally in Middletown, Pennsylvania, that evening, and held public events at the White House in the coming days.

Meadows has dodged questions surrounding Trump and COVID-19 since the president tweeted in the early hours of Oct. 2 that he tested positive, at the time, repeatedly refused to tell reporters when he had last tested negative.

Two senior Trump officials later told ABC News Chief Washington Correspondent Jon Karl they had heard Trump tested positive before the debate but Meadows told Karl several months ago that was not true.

“Some people say you first got — you got an initial positive test even before the debate. Is that true or is that not true?” Karl asked Trump in a March 18 interview at Mar-a-Lago for his new book, “Betrayal: The Final Act of the Trump Show.”

“No,” Trump responded. “No, that’s not true.”

In a new statement on Wednesday, the former president called the reporting “fake news” — but did not flat out deny that he had tested positive before the debate.

“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,” he said.

Notably, Meadows did not write explicitly, according to The Guardian excerpts, that Trump had COVID-19 before the debate but that he had an initial positive test that was followed by a more reliable negative test.

Copyright © 2021, ABC Audio. All rights reserved.