President Donald Trump’s condition is improving as he is being treated for Covid-19 at a military hospital, and he could return to the White House as early as Monday, where his treatment would continue, the doctors leading his treatment said on Sunday.

Doctors provided Trump supplemental oxygen twice during his battle with the lung disease, on Thursday and Friday, and have also given him dexamethasone, they told reporters the day after a series of contradictory messages from the White House caused widespread confusion about Trump’s condition.

Dexamethasone is shown in studies to improve survival for patients hospitalised with critical Covid-19 who need extra oxygen. But it should not be given in mild cases since it can limit the body’s own ability to combat the virus, according to guidelines from the Infectious Disease Society of America.

“The fact of the matter is that he’s doing really well,” Dr Sean P. Conley told reporters at Walter Reed National Military Medical Centre, where Trump has been receiving treatment since Friday.

Doctors said Trump had not run a fever since Friday and that his liver and kidney function remained normal after the second dose in a five-day course of remdesivir, an intravenous antiviral drug that has been shown to shorten hospital stays.

Dr Brian Garibaldi said Trump was given dexamethasone in response to “transient low oxygen levels”.

“He received his first dose of that yesterday and our plan is to continue that for the time being,” Garibaldi said.

Trump is also being given an experimental treatment, Regeneron’s REGN-COV2, as well as zinc, Vitamin D, famotidine, melatonin and aspirin, his doctors have said.

Trump released a four-minute video on Saturday in which he said the “real test” of his condition would come over the next few days.

“Over the next period of a few days, I guess that’s the real test, so we’ll be seeing what happens over those next couple of days,” Trump said into the camera, looking tired and wearing a jacket and open-necked shirt.

Differing assessments of Trump’s health from administration officials on Saturday left it unclear how ill the President had become since he tested positive for the coronavirus on Thursday night.

A White House team of doctors said on Saturday morning Trump’s condition was improving. Within minutes, White House chief of staff Mark Meadows gave reporters a less rosy assessment, saying: “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.”

Meadows, whose initial comments were delivered on condition that he not be identified, altered his tone hours later, telling Reuters that Trump was doing “very well” and that “doctors are very pleased with his vital signs”.

Conley commented on the contradictory assessments on Sunday. “I was trying to reflect an upbeat attitude of the team and the President about the course his illness has had,” Conley told reporters on Sunday. “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, which isn’t necessarily true.”