White House officials are mum about a photograph that appeared on Twitter showing Donald Trump shaking hands with a congressman who has put himself in self-quarantine over coronavirus fears.

Rep. Doug Collins of George, a longtime and fierce Trump ally, is spending the next two weeks at home after shaking hands earlier this month with a man who has tested positive for the disease, for which there is no vaccine nor treatment drug. That took place at the Conservative Political Action Conference near Washington.

Mr Trump also attended and shook hands with Matt Schlapp, the event's director, before giving a speech that turned into another campaign rally. Mr Schlapp has reported shaking hands with the infected man, and Mr Collins also had contact. (So, too, did Texas Senator Ted Cruz, a Trump rival-turned-ally. He's also self-isolating in the Lone Star State.)

A photograph posted online shows Mr Trump shaking hands with Mr Collins on Friday in Atlanta, as he arrived for a tour at US Centers for Disease Control and Prevention (CDC) headquarters there.

White House Press Secretary Stephanie Grisham and her top deputies had not responded to an inquiry seeking comment.

But earlier Monday, she insisted the president is feeling fine.

"I'll tell you what, with our president – this man who doesn't sleep and who I have seen work 15-16 hours a day every day – I have no problem thinking that he's going to be just fine and just healthy," she told Fox News.

Ms Grisham has not responded to several emails from The Independent asking if the president has been tested for coronavirus.