The president is facing questions about the wisdom of holding events with hundreds of supporters, often without social distancing, as on Wednesday night in Minnesota, the day before his positive test.
During Tuesday night’s debate against Mr Biden in Cleveland, Ohio, members of the Trump family were seen removing their face masks while watching in the room despite rules saying only the two candidates and the moderator could do so.
A flood of supportive messages from world leaders came yesterday, including from Boris Johnson, who The Daily Telegraph understands texted Mr Trump a message of goodwill.
The Prime Minister also tweeted: “My best wishes to President Trump and the First Lady. Hope they both have a speedy recovery from coronavirus.”
Vladimir Putin, the Russian president, Angela Merkel, the German chancellor, and Recep Tayyip Erdoğan, the Turkish president, were among other leaders to express their support.
Senior Republicans figures moved to reassure the nation that there would be no disruption to the running of the US federal government despite the sudden development.
Mr Meadows said: “The American people can rest assured that we have a president that is not only on the job, will remain on the job and I’m optimistic that he’ll have a very quick and speedy recovery.”
Mr Meadows joked that the US president had already given him five or six things to do on Friday morning, as he does every day, and that he would be reporting back to him later. Kayleigh McEnany, the White House press secretary, said of the president: “He’s hard at work. We’re having to slow him down a little bit.”
Mr Trump was said to have made calls to Mr Meadows as well as Republican senators Mitch McConnell, the Republican leader in the Senate, and Lindsey Graham, a close confidant of the president.
“Just finished a great phone call with POTUS. He’s in good spirits and we talked business,” Mr McConnell tweeted on Friday saying they discussed the confirmation process for his choice to fill the open Supreme Court seat.
Speculation was rife on Friday that the Republicans may need to slow down their push to get Amy Coney Barrett, the president’s nominee for the Supreme Court, confirmed before the election because of the new coronavirus outbreak at the heart of power.
Ms Barrett, who was unveiled as his nominee by the president the Friday before last, got a negative result from a test yesterday. She reportedly had Covid-19 earlier in the year, likely decreasing her chances of catching the virus again.
Mr McConnell said he would be pushing ahead with the confirmation process. The Republicans want her to be voted through by the Senate before the election.
The White House outbreak also raised questions about whether the two remaining head-to-head debates between Mr Trump on October 15 and October 22 will go ahead.
Guidelines from the US Centers for Disease Control and Prevention (CDC) say someone with Covid-19 can stop quarantining 10 days after their symptoms first appeared if they have gone 24 hours without a fever, meaning Mr Trump could still make the first debate.
Melania Trump tweeted yesterday: “Thank you for the love you are sending our way. I have mild symptoms but overall feeling good. I am looking forward to a speedy recovery.”
Nancy Pelosi, the Democratic speaker of the House of Representatives, said she was praying for the president but also criticised his past behaviour over the virus.
She said: ““This is tragic, it’s very sad. But it also is something that, again, going into crowds unmasked and all the rest was sort of a brazen invitation for something like this to happen.”