Video report by ITV News Washington Correspondent Robert Moore
The President has spent his first night in hospital, closely monitored by doctors watching for any signs that his condition is deteriorating.
Late last night, the President tweeted out his first comment, saying it was "going well, I think."
He is in Walter Reed military hospital in Bethesda, Maryland, eleven miles north of the White House, and he is expected to stay there for several days at a minimum. Last night, as he departed aboard Marine One, he managed to walk unaided to the helicopter, wearing a mask and saying nothing to reporters.
Before he left, however, he tweeted out some comments in which he thanked Americans for their support.
For a man who has long regarded physical ailments as a sign of political weakness it was a humiliating and sombre moment. Four years ago, he was mocking Hillary Clinton for stumbling and appearing weak after a case of suspected pneumonia.
Now he is in hospital 31 days before an election, and with no way of knowing when - or if - he can get back on the campaign trail.
Most ominously, Donald Trump was given an experimental cocktail of drugs, including Regeneron, to combat coronavirus. That has raised eyebrows across the infectious disease community. Why would you use a President as a guinea pig?
But overnight the doctors issued a medical update, saying the President was doing well, did not need supplemental oxygen, and was taking Remdesivir as a therapeutic treatment.
The President's health is a national security issue since he is also the commander-in-chief. An aide carrying the "football" - the briefcase containing the code authorizations for the launch of nuclear missiles - was seen boarding the chopper that took Trump to hospital.
If Trump's health deteriorates much more, and he is unable to exercise his duties, then the 3rd Section of the 25th Amendment will be invoked and power and presidential authority will be transferred to the VP, Mike Pence.
There is no sign that is imminent. But we can't be certain, and there is little confidence that the White House is being candid or transparent in its brief statements
They have misinformed the press on so many occasions there is now a major credibility crisis when the truth matters the most.
It is also looking probable that an event on the South Lawn a week ago - when Judge Barret was nominated for the Supreme Court - might have been a super-spreader event. Several Senators appear to have caught the virus there. So, it seems, did Kelly Anne Conway, a former senior aide to Trump.
There are multiple ironies to what's happening.
The cavalier President who often dismissed the virus is now in hospital. The celebration of a right-wing Judge may have been not the political triumph it was billed as, but a disaster that could have seeded the infection into the heart of the West Wing.
But let's put that to one side. A US President is facing a health crisis - the worst for a US leader since Ronald Reagan was shot in 1981.
Let us hope that with some outstanding medical care that the President can recover and give America the two gifts it needs the most - a choice at the ballot box, and a route out of the pandemic.