(Bloomberg) —

Brian Garibaldi, a member of the president’s medical team and a pulmonary expert at Johns Hopkins University, said “our hope is that we can plan for a discharge as early as tomorrow to the White House” as Trump continued to receive treatment at Walter Reed Medical Center after disclosing on Friday that he’d tested positive for Covid-19.

“The president has continued to improve,” the White House physician, Sean Conley, told reporters in a briefing by the medical team on Sunday morning. “As with any illness, there are frequent ups and downs over the course.”

Conley revealed that Trump has been administered a medicine to control inflammation, and he acknowledged for the first time that the president was given supplemental oxygen on Friday at the White House.

Although aides suggested that Trump will soon be ready to return to the campaign trail with the election just a month away, doubts persist about how sick the president has been as he heads into an phase where some patients’ conditions worsen suddenly and dramatically.

“We know that in many patients who do get very sick, it happens around day 8 to 10,” said Helen Boucher, chief of the division of geographic medicine and infectious diseases at Tufts Medical Center in Boston.

At Sunday’s briefing, Conley said that Trump’s blood-oxygen saturation level dropped twice since his diagnosis, and that the president’s medical team decided after some debate to administer dexamethasone, a steroid used to treat inflammation in Covid patients. Asked about X-rays and CT scans of the president’s lungs, Conley said there were “some expected findings” but nothing “of any major clinical concern.”

QuickTake: Trump’s Treatment and the Options

Trump has already been administered an experimental “antibody cocktail” as well as remdesivir, an antiviral drug.

During a briefing on Saturday, Conley said flatly that Trump hadn’t been administered oxygen on Friday, then hedged to say he hadn’t received it at Walter Reed.

Trump was “adamant that he didn’t need it,” Conley said Sunday, and his blood-oxygen saturation was restored to about 95% after about a minute of supplemental oxygen at the White House. The president remained on oxygen for less than an hour, Conley said, and he hasn’t needed the treatment or seen a recurrence of fever since Friday.

Asked why he didn’t disclose the information earlier, Conley said, “I was trying to reflect the upbeat attitude that the team, the president, that his course of illness had had. I didn’t want to give any information that might steer the course of illness in another direction, and in doing so, it came off that we were trying to hide something that wasn’t necessarily true.”

He concluded Sunday’s briefing after only about 10 minutes, refusing to answer repeated questions about whether scans of Trump’s lungs had shown any sign of pneumonia.

‘Campaign Trail’

Earlier Sunday, a senior campaign aide said the president will soon be “ready to get back to the campaign trail.”

Jason Miller said on NBC’s “Meet the Press” that in a phone conversation on Saturday afternoon Trump, who has for months defied public health recommendations to wear a mask and maintain social distance, wants “to remind folks to wash their hands, use hand sanitizer, make sure that if you can’t socially distance to wear a mask.”

Asked about a new NBC-Wall Street Journal poll that shows Biden leading Trump by 14 percentage points, Miller said on ABC’s “This Week” that the campaign is upbeat about Trump’s prospects in key battleground states needed to get to 270 electoral votes. In the poll taken after Tuesday’s president debate but before Trump was diagnosed with Covid-19, Biden led Trump 53% to 39%, the biggest lead of the presidential campaign.

The president’s aides took to the Sunday news shows seeking to dispel doubts about his re-election campaign and defend his campaign rallies and White House events where Trump and his supporters seldom wore masks.

“We give them a mask, we check their temperature,” Miller said, scoffing that Democratic candidate Joe Biden often “used the mask as a prop.” Trump also has ridiculed Biden for wearing a mask in his public appearances.

Miller said Trump is “going to defeat” the virus. “And I think when President Trump gets to the White House and out on the campaign trail that it’s going to be a slingshot going forward,” he said.

But National Security Adviser Robert O’Brien, who came down with the virus earlier and has recovered, was more cautious, underscoring that it’s too soon to know how Trump will fare.

Asked about a potential transfer of power should Trump’s situation deteriorate, O’Brien said, “We’ve got a great team in place and the president is firmly in control.”

Miller, the campaign adviser, promoted what’s being billed as “Operation MAGA,” with a virtual event on Monday night followed by Vice President Mike Pence, Trump family members and surrogates fanning out after the vice presidential debate scheduled for Wednesday night in the effort to generate momentum in Trump’s absence.

Aides Stricken

Trump aides including Hope Hicks, campaign manager Bill Stepien and supporters including former New Jersey Governor Chris Christie and Republican Senators Thom Tillis, Mike Lee and Ron Johnson have come down with Covid-19, raising questions about whether Trump’s White House and campaign events have become super spreader locations for the virus.

Miller said he and other Trump aides and advisers “keep distance from the president at all times” and Trump “is one of the most tested people the country.”

Steve Cortes, another Trump campaign adviser, defended the president’s actions leading up to his illness, including broadly disregarding health authorities’ guidance.

“He took reasonable risks, not reckless ones,” Cortes said on “Fox News Sunday.” “This president is going to recover, we are highly confident of that, and again, he is a fighter in every sense of the word and he’s doing very well.”

Pence will continue to campaign and there’ll be no delay in the Senate’s confirmation of Amy Coney Barrett, Cortes said.

The best presidents came to understand it’s important to share truth with the American people, David Gergen, a former White House aide to both Democrats and Republicans. Almost 3.3 million people have already cast ballots for the Nov. 3 election, according to data compiled by University of Florida professor Michael McDonald, and it’s unacceptable that voters don’t know the extent of Trump’s condition, Gergen said.

“The voters should have full information about the outlook for the president’s health before they cast a vote,” Gergen said on CNN. “We need to understand just how serious is this going to be for the future health of President Trump if he were to win re-election.”

Read more: Trump’s Covid Treatment and What the Options Are: QuickTake

–With assistance from Alan Levin, Drew Armstrong, Justin Sink and Mark Niquette.