President Donald Trump's doctors said Sunday they had started treating him with dexamethasone, a steroid that shows promise for severely ill patients but can harm patients with less severe cases of Covid-19.
The reveal, which came as part of an upbeat briefing on the president's condition, raised further questions about Trump's health as the 74-year-old grapples with the virus that has killed more than 200,000 Americans.
Dr. Nahid Bhadelia, an infectious disease doctor at Boston University School of Medicine, said the steroid treatment suggests Trump has levels of inflammation that warrant steroid use, although the drug also suppresses the immune system.
"That they made a conscious decision that the benefits of steroids outweigh the risk implies a higher severity than what we knew on Friday and Saturday," Bhadelia said in an email.
Another expert, Dr. Vin Gupta said the doctors' indications could suggest that Trump may have pneumonia.
"The treatment the doctors are reporting suggests the president has COVID pneumonia of at least mild severity," said Gupta, a faculty member at the University of Washington's Institute of Health Metrics and Assessment.
The briefing took place outside the Walter Reed National Military Medical Center in Bethesda, Maryland, where the president has been treated since Friday.
The White House Doctor, Dr. Sean Conley said the president's medical team had started treating the president with dexamethasone. The course of treatment was in response to two incidents where Trump's blood oxygen levels had dropped below normal in the past few days.
Conley also said that Trump could be fired as early as Monday and that his health was improving.
Bhadelia said she generally wouldn't fire anyone who was only given steroids.
The Trump medical team's announcement made it difficult to gauge just how bad the president's case is, especially given the insolence surrounding details about the president's health.
According to the World Health Organization, dexamethasone has been shown to lower 28-day mortality in patients with severe and critical cases of Covid-19. In contrast, the organization found that it "may increase the risk of death when given to patients with non-severe" cases of the disease.
The WHO defined severe cases of Covid-19 as the cause of blood oxygen levels falling below 90%. Healthy adults generally have blood oxygen levels of 95% or more. Rapid breathing or other signs of shortness of breath can also result in a case being classified as severe.
A study cited by the WHO showed that dexamethasone reduced mortality to about 22.9%, compared to 25.7% with standard treatments.
Trump's doctors declined to say how low the president's blood oxygen had dropped, other than not being recorded in the low 80s. Conley said Trump's blood oxygen level was 98% on Sunday.
Dr. Scott Gottlieb, who headed the FDA from 2017 to 2019, said the president's two drops in blood oxygen levels do not suggest a strong recovery.
"I'm worried about the O2 because it means his lungs are affected (COVID-19 is the part of the disease and now he has that)," Gottlieb said in an email. He added, "If they fire him tomorrow, it would mean he is virus negative. I don't think that's possible."
Gottlieb added, "The low oxygen levels and the statement that his" chest imaging had results consistent with his condition "suggest that he may have pneumonia."
On Saturday, Conley dodged questions about whether the president had been given supplemental oxygen. Then on Sunday, Conley said the president's oxygen levels went down Friday and Saturday, and he announced that the president had been given extra oxygen on Friday.
However, it wasn't clear if Trump received oxygen on Saturday. When Conley was asked about this on Sunday, he turned to the nursing staff.
"I'd have to, I'd have to check with the nursing staff. I don't think so – if he did it was very, very limited. But he has no oxygen," Conley said. "The only oxygen I ordered was that Friday morning."
The president's medical team failed to inquire about his condition and forced the public to read between the lines.
"I didn't want to give any information that might steer the course of the disease in any other direction, and it turned out that we were trying to hide something that wasn't necessarily true," said Conley on Sunday.
Still, it seemed odd to the doctors that given the dexamethasone treatment, the President only needed supplemental oxygen once or twice. The National Institutes of Health Covid-19 treatment guidelines indicate that dexamethasone only has beneficial effects in patients who require supplemental oxygen.
"Dexamethasone is an incredibly common steroid. But not in the high doses used in COVID-19, which is why the NIH AGAIN recommends its use unless the (patient) needs supplemental oxygen," wrote Dr. Kavita Patel, a former executive director of the Transformation Clinic at the Brookings Institution's Health Policy Center, in a post on Twitter on Sunday.
"Not a second of oxygen here or there," she wrote.
– CNBC's Shepard Smith contributed to this report.
Disclosure: Scott Gottlieb is a CNBC employee and a member of the boards of directors of Pfizer, the genetic testing startup Tempus, and the biotech company Illumina. Pfizer has signed a manufacturing agreement with Gilead to manufacture Remdesivir. Gottlieb is also co-chair of Norwegian Cruise Line Holdings and Royal Caribbean's Healthy Sail Panel.
Correction: This story has been updated to take into account that Sean Conley, the President's Doctor, did not say whether the President was given supplemental oxygen on Saturday.