Dr. Anthony Fauci refused to evaluate whether President Joe Biden is fit to lead based on his poor debate performance against former President Donald Trump last week.

Fauci, a longtime director of the National Institute of Allergy and Infectious Diseases (NIAID) who advised both Trump and Biden before retiring at the end of 2022, spoke about the issue on “The Takeout” podcast.

CBS News Chief Washington Correspondent Major Garrett asked Fauci if there was anything that would “medically alarm” him based on what he saw during the debate.

Dr. Fauci tells @MajorCBS that he has "no doubt" President Biden has the mental capacity and vigor to carry on with his office, despite a shaky performance during last week's debate with former President Donald Trump.

Full episode with Dr. Fauci on @TakeoutPodcast will be… pic.twitter.com/lVpwjNYcVP

— CBS News (@CBSNews) July 2, 2024

Fauci, 83, demurred, noting that he thought it would be “inappropriate” to say.

Looking at someone on a “one-shot basis” leaves too much room for unknowns, including questions about whether Biden had a “bad cold” or did he “take an antihistamine to make him groggy,” Fauci explained.

“We don’t know what went on and I think it would be unfair and inappropriate to try and diagnose something from just a 90-minute clip,” he added.

Biden, 81, seeks to reassure Democrats that he remains capable of serving and running for re-election as he faces growing pressure to step aside and give the party a chance to rally behind a replacement.

During the debate, sources close to Biden began telling news outlets the president had been suffering from a cold. But White House Press Secretary Karine Jean-Pierre told reporters Biden “was not taking any cold medication.”

Fauci also told Garrett that, based on his interactions with Biden, he has “no doubt” that Biden has the vigor and mental capability to continue serving as president.

The interview took place as Fauci promoted his new book, “On Call,” which he said describes how Biden asked “probing” questions and was “analytical” in his discussions with the president.

Fauci said what he witnessed during the debate last week did not reflect his personal experiences with Biden, adding, “To me, it just looked like a bad night.”

In another recent interview on CBS prior to the debate, Fauci said Biden was “absolutely” fit to lead for another term while criticizing what he described as Trump’s “missed opportunities” from a “health standpoint.”