Contrary to medical advice, it was handshakes all around at the White House on Friday as U.S. President Donald Trump introduced business leaders at a press conference on tackling the coronavirus outbreak.

U.S. medical authorities say the virus is thought to spread between people in close contact, and "social distancing" has become a watchword around the world.

But after declaring a national state of emergency and calling for people to take "common sense measures" to prevent infection, Trump shook hands with several speakers as they took turns at the podium.

Just one executive avoided the president's outstretched hand.

Bruce Greenstein, CEO of the home healthcare provider LHC, instead gave Trump an elbow bump, after which the president declared, "I like that. That's good."

Trump, 73, was pressed on whether he should be tested after coming into contact with a Brazilian official now known to have COVID-19.

He initially shut down the question, saying that on the advice of White House doctors, "I don't have any of the symptoms."

But later he changed tack, saying: "I didn't say I wasn't going to be tested" and that he "most likely" would be, "fairly soon."