Dr. Fauci ducks on weighing in on Biden's health but makes surprising admission about what medication the president is likely taking

Former Chief Medical Advisor to the President of the United States Dr. Anthony Fauci dodged questions about Joe Biden's health after the president's concerning debate performance. 

CBS host Major Garrett asked Fauci Tuesday if during the debate he saw anything that would 'medically alarm' him. 

The pandemic patriarch demurred, saying 'You know, I can't say.'

'I think it would be inappropriate to say that, Major, because when you're just looking at someone on a one-shot basis, you just don't know what could happen,' Fauci said.

The doctor did suggest, however, that some medication could be behind Biden's sleepy showing. 

'Did he have a bad cold? Did he take an antihistamine to make him groggy or what have you? We don't know what went on,' Fauci continued.

Antihistamines, the medication Fauci mentioned, are commonly used to relieve allergies and cold and flu symptoms. Benadryl and Claritin are popular versions of the medicine in the US. 

Some are known to cause users to get sleepy, which Fauci seemed to be suggesting may have happened with Biden on stage during his debate performance. 

And Biden himself even admitted that he nearly dozed off on stage.  

The 81-year-old president made the admission during a fundraiser in the ritzy D.C. suburb of McLean, Virginia Tuesday night.

He told the crowd he 'wasn't very smart' for 'traveling around the world a couple times' before his televised showdown with former President Donald Trump.

Biden did back-to-back trips to France for a D-Day anniversary celebration and then onto Italy for the G7 in June. 

'I decided to travel around the world a couple of times … shortly before the debate …I didn’t listen to my staff … and then I almost fell asleep on stage,' the president said.

Upon his return, the president took a holiday at his vacation home in Rehoboth Beach, Delaware. 

Then Biden spent a whole week at the presidential retreat Camp David resting and preparing for the debate. 

The New York Times reported Tuesday that Biden was so drained from the jetsetting that advisers cut debate prep short by two days - in order to fit in the beach trip.

While at Camp David, debate prep didn't start before 11 a.m. and Biden was given time each day in the afternoon to take a nap.

The president made the clear at the Tuesday campaign event his travel is 'not an excuse but an explanation.' 

Fauci, similarly agreed, saying his prognosis of Biden's bill of health would not be appropriate since the debate was too short to get an accurate assessment.  

'I think it would be unfair and inappropriate to try and diagnose something from just a 90-minute clip,' he said. 

Then the doctor said the same line many leading Democrats have used of the debate: 'It just looked like a bad night.' 

'My interactions with him, I have to say, have been very, very positive,' Fauci added.