Outgoing acting White House chief of staff Mick Mulvaney is under voluntary self-quarantine in his home state of South Carolina after his niece had contact with one of the Brazilian officials who tested positive for coronavirus, a senior White House source confirms. Mulvaney has tested negative, but is protectively awaiting the results of his niece, who lives in Mulvaney's Washington, D.C., residence.

Mulvaney's niece interacted with the Brazilian president's press secretary, Fabio Wajngarten, more than a week ago in Florida. President Trump hosted the Brazilians at his Mar-a-Lago estate. The Associated Press first reported Mulvaney's self-quarantine.

"Mulvaney had contact with someone whose test results are pending, so out of an abundance of caution due to his proximity to the President, he's teleworking pending those results," said White House press secretary Stephanie Grisham, who is also being cautious and working from home.

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The president's incoming chief of staff, Republican Congressman Mark Meadows, also self-quarantined briefly after interacting with someone carrying the virus at the Conservative Political Action Conference outside D.C. last month, Meadows has been back at the White House since then.

Mr. Trump announced Meadows would be replacing Mulvaney earlier this month.

White House employees who can work from home have been encouraged to do so. Meanwhile, the Coronavirus Task Force, which briefs reporters almost daily from the White House briefing room, stands shoulder-to-shoulder on the podium, not in keeping with the social distancing practices encouraged by public health officials.

On Monday, the president told reporters this outbreak could last into July or August.

Kathryn Watson contributed to this report.