Wearing a mask and suit, Trump walked out across the White House lawn on Friday afternoon to his helicopter, Marine One, for the short flight to Walter Reed National Military Medical Center in Washington DC.
Doctors said the president was “fatigued but in good spirits”.
So far, Trump has been treated with an experimental drug cocktail and the antiviral medication Remdesivir.
Tests have shown Remdesivir, originally developed as an Ebola treatment, can cut the duration of symptoms.
On Friday night, Trump’s physician, Sean Conley, issued a statement that read: “I am happy to report the president is doing very well.”
A number of other people who came into close contact with Trump, including his wife Melania, have tested positive.
This includes close aide Hope Hicks – believed to be the first to show symptoms – campaign manager Bill Stepien and former White House counselor Kellyanne Conway.
Republican Senators Mike Lee and Thom Tillis have also tested positive.
In a video posted to Twitter, Trump said: “I think I’m doing very well. But we’re going to make sure that things work out. The first lady is doing very well. So thank you very much.”
Shortly before midnight, he tweeted again: “Going well, I think! Thank you to all. LOVE!!!”