Oct. 3 (UPI) -- White House physician Dr. Sean Conley said Saturday that President Donald Trump "is doing very well" after treatment at Walter Reed hospital, but threw the timeline of his illness into question and later said the president is "not out of the woods."
Conley and a team of several doctors from Walter Reed National Military Medical Center briefed the public on Trump's condition and treatment outside the facility midday Saturday.
"This morning, the president is doing very well," Conley said.
He said Trump experienced symptoms including a mild cough, nasal congestion and fatigue beginning Thursday, but that those conditions have since improved.
Conley said Trump's been fever free for more than 24 hours, has been walking around and tending to some work.
"We remain cautiously optimistic, but he's doing great," he said.
Conley said Trump is "not on oxygen right now," nor was he on Friday, but declined to clarify when reporters asked if Trump had ever been on oxygen to treat coronavirus.
CNN and The New York Times reported Trump received oxygen at the White House on Friday.
"At this time, the team and I are extremely happy with the progress the president has made.
Though the doctors offered a positive outlook for the president's condition, a source familiar with the president's health offered a different picture to a White House pool reporter attending the news conference.
"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. We're still not on a clear path to a full recovery," the source said, speaking on the condition of anonymity.
Mark Meadows, the White House chief of staff, said Trump's oxygen levels fell rapidly Friday.
"The biggest thing that we see is that with no fever now, and with him doing really well with his oxygen saturation levels," Meadows said in an interview with Fox News host Jeanine Pirro on Saturday night. " Yesterday morning, we were real concerned about that. He had a fever, and his blood oxygen level had dropped rapidly."
On Saturday afternoon, Trump tweeted praise for those caring for him at Walter Reed.
"Doctors, Nurses and ALL at the GREAT Walter Reed Medical Center, and others from likewise incredible institutions who have joined them, are AMAZING!!! Tremendous progress has been made over the last 6 months in fighting this PLAGUE. With their help, I am feeling well!," he tweeted at 1:19 p.m.
Later Saturday, a 4 minute video by Trump was posted on his Twitter feed. "I came here, wasn't feeling so well. I feel much better now. We're working hard to get me all the way back. I have to be back, because we still have to make America great again. We've done an awfully good job of that, but we still have steps to go and we have to have to finish that job."
He added that he thought he would "be back soon. And I look forward to finishing up the campaign, the way it was started and the way we've been doing, the kind of numbers that we've been doing, we've been so proud of it. But this was something that happened, and it's happened to millions of people all over the world, and I'm fighting for them, not just in the U.S., I'm fighting for them all over the world. We're going to beat this coronavirus or whatever you want to call it, and we're going to beat it soundly."
Ivanka Trump, the daughter of the president and a White House senior adviser, posted a photo of Trump working in the presidential suite at the hospital.
On Friday, Conley said doctors at the hospital administered remdesivir therapy to the president. Before Trump's admittance to Walter Reed, he also was given an experimental antibody treatment called regeneron.
Late Saturday, Conley wrote an update saying Trump was given a second dose of the drug. "While not out of the woods, the team remains cautiously optimistic. This plan for tomorrow is to continue observations in between doses of Remdesivir, closely monitoring his clinical status while fully supporting his conduct of Presidential duties."
Conley says he "remains fever-free and off supplemental oxygen with a saturation level between 96 and 98% all day."
Comments at Saturday's news conference about Trump's diagnosis and the administration of the antibody treatment caused confusion about the timeline of the president's illness.
Conley told reporters they were "72 hours into the diagnosis," which would place his positive test about midday Wednesday. Trump tweeted the news just before 1 a.m. Eastern time Friday.
"Tonight, @FLOTUS and I tested positive for COVID-19. We will begin our quarantine and recovery process immediately. We will get through this TOGETHER!" Trump tweeted.
Additionally, the medical team said Trump was given the antibody treatment "48 hours ago," or midday Thursday.
Conley later walked back the timeline he presented during the news conference in a memo issued to reporters.
"This morning while summarizing the president's health, I incorrectly used the term 'seventy two hours' instead of 'day three' and forty eight hours' instead of 'day two' with regards to his diagnosis and the administration of the polyclonal antibody therapy.
"The president was first diagnosed with COVID-19 on the evening of Thursday, October 1st and had received Regeron's antibody cocktail on Friday, October 2nd."
Marine One transported Trump to the Bethesda hospital Friday evening for what White House officials said was likely to be a "few days."Remdesivir, manufactured by Gilead Sciences under the brand name Vaklury, is an antiviral drug originally developed to treat hepatitis C, which was unsuccessful. It was later determined to work against multiple viruses, including coronavirus.
Clinical results for the antiviral in COVID-19 trials have been mixed, with one study in August showing the drug doesn't improve outcomes in people hospitalized with moderate pneumonia caused by COVID-19.
But research published in May suggested the drug might be effective in people with severe COVID-19.
A study published by the New England Journal of Medicine found that seriously ill patients infected with the new coronavirus had an average recovery time of 11 days after receiving the drug, compared to 15 days for those given a placebo.
Research published last month showed that remdesivir administered in combination with baricitinib -- treatment for rheumatoid arthritis -- can reduce the recovery time for people with COVID-19 when compared to people treated with just the antiviral.
Remdesivir works by slowing the production of enzymes that play a key role in the replication of viruses, including coronaviruses, according to Gilead Sciences.