Coronavirus: Trump says he 'understands' Covid after weekend in hospital

President Donald Trump has said he "understands" and has "learned a lot" about Covid-19 after a weekend in which he received supplemental oxygen, a cocktail of drugs and was hospitalised after testing positive for the disease.

"It’s been a very interesting journey. I learned a lot about Covid. I learned it by really going to school. This is the real school," said Mr Trump, 74, in a pre-recorded address from the Walter Reed Medical Center presidential suite.

Mr Trump was helicoptered to the Maryland hospital on Friday after experiencing fever and a drop in his oxygen levels. 

"And I get it, and I understand it, and it's a very interesting thing, and I’m going to be letting you know about it," he added, in a video uploaded to social media on Sunday.

The White House was thrown into disarray last week when it was confirmed both the president and first lady, 50, had tested positive for coronavirus, which has claimed some 210,000 US lives and crippled the economy.

It is unclear how the president might have contracted Covid-19, though he had been in close contact with aide Hope Hicks who tested positive for coronavirus on Thursday. With less than a month to go until election day, a number of the president's key allies have since tested positive for the illness.

Calls are growing for the president's medical team to be more open and honest about his condition following a weekend of contradictory statements.

Giving an update on Mr Trump’s condition on Saturday, Dr Sean Conley said he was feeling well and in "exceptionally good spirits", a message that appeared far rosier than the one later given by the president’s chief of staff.

Mark Meadows told reporters Mr Trump’s vitals had been very "concerning" and that the next few days would be critical, leading to accusations that the president's medical team were not revealing the full picture.

In a second update on Sunday, the president's doctors said he could be discharged on Monday –despite having been given dexamethasone, a steroid that is usually only used on the sickest coronavirus patients. They also confirmed that Mr Trump's oxygen levels dropped twice, after avoiding questions on the issue the previous day.

In Sunday's social media video the president vowed to greet supporters who had been waiting outside the hospital in support. Shortly afterwards, he was spotted in the back of his motorcade waving to fans, some of whom have been at the site for days offering support.

While the president was wearing a face mask, questions will be raised over the safety of the excursion, with people diagnosed with coronavirus asked to quarantine for 10 days after first experiencing symptoms.

Dr James P Phillips, a CNN media contributor and an attending physician at the Maryland hospital, attacked the president's political theatre as "insanity".

"That presidential SUV is not only bulletproof, but hermetically sealed against chemical attack. The risk of Covid-19 transmission inside is as high as it gets outside of medical procedures," Dr Phillips said in a tweet.

"The irresponsibility is astounding. My thoughts are with the Secret Service forced to play."