Source tells reporters next 48 hours 'critical' for Trump after physician says he's doing well

WASHINGTON -- A source familiar with US President Donald Trump's health told reporters on Saturday that the next 48 hours will be critical for the president after doctors said he is doing well.

"The president's vitals over the last 24 hours were very concerning," the source said in comments passed along to the media by a member of the White House press pool. "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 statement came shortly after White House physician Sean Conley said Saturday morning that Trump, who is staying at a military hospital for COVID-19 treatment, is "doing very well".

"At this time, the team and I are extremely happy with the progress the president has made," Conley briefed reporters from the Walter Reed National Military Medical Center in Bethesda, Maryland. "The president has been fever-free for over 24 hours."

The physician declined to put a "hard date" for when Trump would be discharged and avoided questions about whether the president was treated with supplemental oxygen prior to Saturday, only saying "he has not needed any today at all."

A source close to the White House told CNN on Saturday that Trump received supplemental oxygen on Friday.

Trump moved to Walter Reed Friday evening, where he is using Remdesivir, a COVID-19 drug made by US biopharmaceutical company Gilead Sciences, as a treatment.

"Doctors, Nurses and ALL at the GREAT Walter Reed Medical Center, and others from likewise incredible institutions who have joined them, are AMAZING!!!" Trump tweeted Saturday afternoon.

"Tremendous progress has been made over the last 6 months in fighting this PLAGUE," he wrote. "With their help, I am feeling well!"

Trump was first diagnosed with COVID-19 Thursday evening, according to a memo by Conley. The president received a dose of an experimental antibody cocktail being developed by US drug maker Regeneron on Friday.

US first lady Melania Trump, who also tested positive for COVID-19, is "doing well," her chief of staff and spokesperson Stephanie Grisham said on Saturday.

"Her symptoms have not worsened and she continues to rest," Grisham noted. "She remains in touch with her husband. She is thinking of all who are ill and wishes them a speedy recovery."

It is not yet clear when and how the Trumps infected with COVID-19.

The president had a packed schedule before testing positive for the virus, including hosting a ceremony to introduce a Supreme Court nominee at the White House rose garden, traveling to Cleveland, Ohio for the first 2020 presidential debate, addressing a rally in Duluth, Minnesota.

A growing number of individuals in Trump's orbit, including three Republican senators, campaign manager Bill Stepien, and former New Jersey Governor Chris Christie who helped the president prepare for the debate, have also contracted the disease.

Vice President Mike Pence and second lady Karen Pence reportedly tested negative for COVID-19 again on Saturday morning.