Washington (AFP) -
US President Donald Trump has resumed making calls and tweeting from hospital, but doctors say his progress on Sunday will be crucial to see if he develops a more severe form of Covid-19.
The president's medical team was due to give an update of the his condition late Sunday morning.
Trump posted a video Saturday from the business suite in Walter Reed medical center near Washington, saying he was improving and would be 'back soon' -- but that the crucial coming days would be 'the real test.'
On Sunday, his deputy campaign manager Jason Miller told ABC he had spoken to Trump for a half-hour Saturday and that the president was eager for political news with the November 3 election less than a month away.
He was even 'cracking jokes,' Miller said.
National security advisor Robert O'Brien also said Trump was doing well, telling CBS that any discussion of a potential transfer of power to Vice President Mike Pence -- as has happened when other presidents underwent surgery or were sedated -- was 'not something that's on the table' for now.
Pence has been close to some of those testing positive but says he has regularly tested negative. As Trump has had to freeze or rework his campaign, the vice president is continuing a busy schedule of appearances.
But serious questions linger over the timing and severity of the president's illness -- and whether he might have exposed dozens of others to Covid-19 even after a close aide tested positive.
A confusing timeline provided by Trump's advisors and doctors suggested that he met with more than 30 donors on Thursday in Bedminster, New Jersey even after learning that close aide Hope Hicks had tested positive -- and just hours before he announced his own positive test.
- Low point -
All this came in a week when one poll -- taken in the two days after a bruising presidential debate with Democratic rival Joe Biden but before news emerged of Trump's illness -- showed his approval rating hitting a low point for the year.
The Wall Street Journal/NBC survey gave Biden a significant a 53-39 percent lead among registered voters.
News of Trump's hospitalization has drawn widespread sympathy but also fueled a sense among some that he was paying a price for months of consistently downplaying the severity of the pandemic.
He mocked Biden's mask-wearing during their debate Tuesday, even as Trump family members in the audience violated rules requiring masks.
Miller said Sunday that Trump had urged him to convey a message to the American people about the importance of wearing masks and taking other precautions -- a message many Democrats said rang hollow.
'You can't just say we need to do something but we're going to let the virus run free. Now it has even run free in the White House,' House Speaker Nancy Pelosi told CBS.
In a video released Saturday, the 74-year-old Trump said: 'I feel much better now,' adding, 'I think I'll be back soon.' He has thanked those sending him get-well messages.
Dozens of Trump supporters have gathered outside the hospital, many waving pro-Trump signs and banners.
But uncertainty remains about the course of the disease, which days after diagnosis can hit recovering patients hard with no warning.
Trump's wife Melania also tested positive but he said her symptoms were not severe.
- 'We were real concerned' -
Late Saturday, White House doctor Sean Conley said Trump was 'not yet out of the woods,' but that the medical team is 'cautiously optimistic.'
White House Chief of Staff Mark Meadows said Trump's condition had aides worried on Friday, but that he had since improved.
'Yesterday morning, we were real concerned... he had a fever and his blood oxygen level had dropped rapidly,' Meadows told Fox News.
But Meadows said there was never a risk Trump would have to hand power to Pence.
'He's made unbelievable improvements from yesterday morning, when I know a number of us, the doctor and I, were very concerned,' Meadows said.
And Conley said Trump remained 'fever-free and off supplemental oxygen.'
Those close to the president who have tested positive include campaign advisor Chris Christie; Nicholas Luna, one of the 'body men' who accompanies the president round the clock, and others who attended an event in the White House Rose Garden last weekend.
Also testing positive were former White House top aide Kellyanne Conway, campaign manager Bill Stepien and Republican senators Thom Tillis, Mike Lee and Ron Johnson.
Public health experts have expressed alarm at the outbreak linked to the September 26 celebration of conservative judge Amy Coney Barrett's nomination to the Supreme Court.
Democrats have called for Barrett's Senate confirmation hearings to be postponed, but Judiciary Committee chair Senator Lindsey Graham said they would go ahead.
Biden, who has recently tested negative, has made Trump's frequent downplaying of the Covid-19 crisis and mixed messaging on mask-wearing a central campaign theme.
With 208,000 American virus deaths and the president hospitalized, that theme -- one Trump had hoped to downplay -- has become inescapable.