Washington (AFP) -
Donald Trump is doing 'very well' in his hospital treatment for Covid-19, his doctors said Saturday, but a source with knowledge of the US president's condition warned his vital signs had been worrying, with the next 48 hours critical.
Trump is mobile, has been fever free for 24 hours and his cough, nasal congestion and fatigue are improving, physician Sean Conley said during the first update since the president was admitted to Walter Reed military medical center near Washington on Friday.
Trump, 74, is not receiving extra oxygen, he added, and is 'doing very well.' A second doctor, Sean Dooley, said the president's cardiac, kidney and liver function were 'normal.'
But a source familiar with the president's health -- later named in US media as White House chief of staff Mark Meadows -- gave a much more worrying assessment.
'The president's vitals over the last 24 hours were very concerning and the next 48 hours will be critical in terms of his care,' he said. 'We're still not on a clear path to a full recovery.'
The White House has not commented officially and Meadows had asked to speak off-the-record before his name appeared as the source in The New York Times and other US outlets.
In one encouraging sign, Trump began tweeting again on Saturday, reassuring that he was 'feeling well' and praising hospital staff.
But Conley was evasive when asked whether the president had received supplementary oxygen at any point since falling ill, only confirming that he hadn't received any at the hospital or on Thursday -- the day of his positive test.
Several US media outlets said Trump was on oxygen at the White House on Friday before being admitted to Walter Reed.
- Confusion -
Conley added to the confusion by suggesting that Trump had been diagnosed on Wednesday -- not on Thursday, per the official account -- but he later said he had misspoken.
Soon after Trump arrived at the hospital, Conley said in a memo the president was starting a course of therapeutic drug remdesivir and had received an eight-gram dose of an experimental antibody cocktail.
Neither Trump's doctors nor the White House explained why the president was taking unproven drugs if his progress was satisfactory.
A handful of supporters set up outside the hospital from early Saturday, one waving an American flag, cheered on by the honking horns of passing cars.
'I'd heard the night prior around two in the morning that (Trump) came down with Covid and saw that he was here,' said Richard Potcner, 40, a Maryland resident sporting a cowboy hat in the colors of the US flag.
'And I just felt compelled to come wish him well and support him.'
Doctors' optimism over the president's recovery prospects has been tempered by news that more people close to Trump have tested positive for the coronavirus.
The latest is campaign advisor Chris Christie, who was among several aides that helped Trump prepare for the first presidential debate who have since announced positive tests.
Christie and a number of senators and Trump aides are also among a growing list from the president's orbit to have tested positive for coronavirus after attending an event in the White House Rose Garden last weekend.
The so-called 'White House cluster' includes first lady Melania Trump, former White House top aide Kellyanne Conway and the president's campaign manager Bill Stepien, as well as Republican senators Thom Tillis and Mike Lee.
Heightening the sense of crisis at the heart of power in America, a third Republican senator, Ron Johnson of Wisconsin, announced on Saturday that he had tested positive.
- 'False sense of comfort' -
Public health experts have expressed alarm at the outbreak linked to a September 26 celebration of conservative judge Amy Coney Barrett's nomination to the Supreme Court.
'They relied too much on diagnostic testing. We know that these tests have a very high false negative rate,' said Ali Nouri, president of the Federation of American Scientists.
'By simply relying on these diagnostics to determine who gets to come in and out of the White House, and by not requiring other protections, like social distancing and masks, they created a false sense of comfort for the White House.'
Trump -- who is well behind his 77-year-old Democratic election rival Joe Biden in the polls -- has been forced to freeze or rework much of his campaign ahead of a potentially messy vote on November 3.
Among the unknowns were the prospects for two remaining presidential debates and whether the president will have to yield power temporarily to Vice President Mike Pence if his condition worsens.
Biden has made Trump's frequent downplaying of the Covid crisis and mixed messaging on mask-wearing a central campaign theme, while Trump has tried to shift the narrative to areas where he feels stronger, like the economy.
The former vice president, who stood on a stage with Trump for 90 minutes during their ill-tempered first debate Tuesday, announced that he and his wife Jill tested negative Friday.
Biden reminded voters during the debate that he has pushed consistently for a serious approach to the coronavirus, which has killed more than 208,000 Americans, unlike his opponent who has mocked the Democrat for his rigorous use of masks.