O’Brien has “mild symptoms and has been self-isolating and working from a secure location off site,” the White House said in a statement Monday.
“There is no risk of exposure to the President or the Vice President. The work of the National Security Council continues uninterrupted,” the White House said.
O’Brien, 54, is among the highest-ranking members in Trump’s orbit reported to have come down with the coronavirus.
But other administration officials have previously been diagnosed with the virus. Vice President Mike Pence’s press secretary Katie Miller tested positive for Covid-19 in May. That same month, a personal valet for Trump, who among other tasks served meals to the president, also tested positive.
Kimberly Guilfoyle, an official on Trump’s reelection campaign and the girlfriend of the president’s oldest son, tested positive in July.
O’Brien earlier this month had traveled to Europe to meet with officials from the United Kingdom, France, Germany and Italy.
More than 4.2 million people in the U.S. have tested positive for Covid-19 and at least 146,900 have died, according to data from Johns Hopkins University.
Bloomberg first reported O’Brien’s diagnosis, citing people familiar with the matter. CNN and Politico followed with reports of their own.
This is breaking news. Please check back for updates.
— CNBC’s Amanda Macias contributed reporting.