“He has mild symptoms and has been self-isolating and working from a secure location off site,” the White House said in a statement. “There is no risk of exposure to the President or the Vice President. The work of the National Security Council continues.”

O’Brien came down with the virus after attending a family event, Bloomberg reported, citing a person familiar with the matter. Earlier this month, he returned from a three-day trip to Paris, where he met with his counterparts from the U.K., France, Germany and Italy, according to Politico.

Several people close to Trump have tested positive for the virus. Vice President Mike Pence’s press secretary tested positive in May, as well as one of Trump’s personal valets. Several Trump campaign staffers, including Kimberly Guilfoyle ― the girlfriend of Trump’s eldest son, Donald Trump Jr., and a top fundraising official for the campaign ― have also tested positive in recent weeks.

White House press secretary Kayleigh McEnany said last week that Trump is the “most tested man in America,” sometimes taking “multiple” tests in one day.