Mr Trump tweeted a video message shortly after arriving back at the White House from the Walter Reed Medical Center.

The President reiterated that he had "learned a lot" about the disease after testing positive to the virus last week and being treated at the hospital.

"One thing that's for certain, don't let it dominate you," he said.

"Don't be afraid of it.

"We're going to beat it. We have the best medical equipment, we have the best medicines all developed recently."

He said that he "didn't feel so good" originally, but two days ago he started to feel "better than 20 years ago" and could have left hospital then.

"Don't let it take over your lives. Don't let that happen," he said.

"We're the greatest country in the world. We're going back to work. We're going to be out front.

"As your leader, I had to do that, I knew there was danger to it.

"I stood out front and led. Nobody that's a leader would not do what I did.

"I know there's a risk, there's a danger. But that's ok. And now I'm better.

"Maybe I'm immune? I don't know."

The vaccines were coming "momentarily", he added

Mr Trump spent three nights in hospital after being admitted on Friday.

He emerged from the hospital on Monday evening wearing a suit and mask and raised a fist and a thumbs up as he walked to his car.

He was then driven a few hundred metres to the presidential helicopter, Marine One, for the 15-minute flight back to the White House where he will continue his recovery.

On arrival, he stood on the White House balcony for several minutes, took off his mask and saluted as the helicopter took off again.

Earlier, the President tweeted that he was "feeling really good" and flagged that he would be leaving the hospital.

"Don't be afraid of COVID," he said in the tweet.

"Don't let it dominate your life. We have developed, under the Trump Administration, some really great drugs & knowledge. I feel better than I did 20 years ago!"

Mr Trump, 74, was taken to the hospital on Friday night after he announced via Twitter that he and first lady Melania had tested positive for coronavirus on Thursday.

Mr Trump was running a high fever and has received supplemental oxygen twice in recent days, according to his White House physician, Dr Sean Conley.

Mr Trump left the military hospital as the scale of the outbreak at the White House itself was still being uncovered.

Press secretary Kayleigh McEnany announced she had tested positive for the virus Monday morning (local time) and was entering quarantine.

Trump not 'out of the woods yet'

Dr Conley said on Tuesday morning (AEST) that Mr Trump "may not entirely be out of the woods yet" but indicated that the majority of his vital signs were good and that he "currently does not have any respiratory complaints".

He added that the President would be surrounded by world-class medical care around the clock at the White House and had not had a fever in more than 72 hours.

Doctors have been treating him with a steroid, dexamethasone, that is normally used only in the most severe cases. He has also been given an experimental dual antibody treatment and the unproven COVID-19 drug remdesivir.

Dr Conley repeatedly declined to share results of medical scans of Mr Trump's lungs, saying he was not at liberty to discuss the information because Mr Trump did not waive doctor-patient confidentiality on the subject.