President Trump’s national security adviser has tested positive for the novel coronavirus, underscoring the persisting threat of COVID-19 – even to the White House – as cases increase in the United States. 

White House national security adviser Robert O’Brien is the highest ranking official to date to contract COVID-19, a virus that, until last week, Trump had sought to minimize. Details about O’Brien’s positive test were closely held at the White House before Bloomberg first reported on the situation Monday.

The development hung over Trump’s trip to Morrisville, N.C., on Monday where he highlighted progress on coronavirus vaccine research through the administration’s “Operation Warp Speed.” 

Before departing for North Carolina Monday afternoon, Trump told reporters at the White House that he hadn’t seen O’Brien “lately” and that he didn’t know exactly when O’Brien tested positive. Trump also said he planned to phone O’Brien later that day.

Trump, beginning last week, was forced to take a more realistic and sober tone when discussing the coronavirus pandemic. After initially dismissing recent spikes in cases, he acknowledged the situation would “get worse before it gets better” and abruptly canceled GOP convention events in Jacksonville, Fla., after forcefully pushing for the event to be held in person. 

O’Brien’s positive test was yet another piece of bad news with which the president must contend. 

The White House confirmed the news in a brief statement to reporters, saying O’Brien has “mild symptoms and has been self-isolating and working from a secure location off site.” The risk to either Trump or Vice President Mike Pence was nonexistent, the White House said. O’Brien reportedly tested positive after taking a few days off with family and is believed to have become infected after his daughter fell ill. 

A handful of others working at the White House or in otherwise close proximity to the president have tested positive for the virus, though none as senior as O’Brien, who is tested regularly because of his interactions with Trump. Last week, a cafeteria employee at the Eisenhower Executive Office Building and a U.S. Marine assigned to the president’s helicopter squadron also tested positive for COVID-19.

“It’s a reminder that no one is safe if precautions are not taken, regardless of where they might work or live,” said Anand Parekh, chief medical adviser at the Bipartisan Policy Center. “There are still nearly 60,000 daily confirmed cases of COVID-19 in the U.S.”

The public attention surrounding O’Brien’s case mirrored that around the disclosure that Pence’s then-press secretary Katie Miller tested positive for the virus in early May. Miller has close contact with Pence and other members of the White House coronavirus task force, and news of her test caused Pence to distance himself from Trump and led members of the task force to self-isolate out of an abundance of caution.

The White House shortly thereafter required aides in the West Wing to wear face masks except when at their desks. That policy, however, was changed in June to recommend, not require, the use of face coverings. The White House in late June also stopped conducting temperature screenings for all visitors and staff entering the complex, citing the District of Columbia’s reopening guidelines.

Asked whether the White House planned to change its protocols in the wake of O’Brien’s positive test, White House spokesman Judd Deere said in a statement that the president’s doctor and White House operations “work closely to incorporate current CDC guidance and best practices to ensure every precaution is taken to keep the President, First Family and the entire White House Complex safe and healthy at all times.”

“In addition to social distancing, readily available hand sanitizer, regular deep cleaning of all work spaces, and facial coverings, those in close proximity to the president continue to be tested for COVID-19 to ensure exposure is limited to the greatest extent possible,” Deere said.

Parekh, who is a former Department of Health and Human Services deputy assistant secretary, said that individuals wear should cloth-based masks in any public setting and recommended the White House make masks mandatory in common areas of the West Wing.

O’Brien is one of Trump’s most prized advisers and regularly briefs him on national security. He last traveled with the president to U.S. Southern Command in Doral, Fla., on July 10 to receive a briefing on efforts to combat drug trafficking. He can sometimes be seen at the White House gaggling with a smaller-than-usual cadre of reporters following television interviews on the White House driveway.

The recent developments at the White House have underscored the importance of access to timely tests to preventing the undetected spread of COVID-19. Testing delays that have befallen the United States as states and localities experience increases in cases make it more difficult to quickly isolate cases and conduct contact tracing. States like Florida, California, and Texas have experienced the most worrying spikes in cases.

While masks are not mandatory on the White House grounds, some officials have encouraged their use by wearing them publicly, including the vice president and the president’s daughter and senior adviser, Ivanka Trump.

O’Brien is among those who have worn a mask, and one administration source said that the national security adviser has been taking the virus very seriously. During a speech back in March, O’Brien urged the public to follow Centers for Disease Control and Prevention guidance on washing their hands, staying home when they feel sick and engaging in some social distancing.

Still, other officials have not worn masks publicly and Trump only recently offered a strong endorsement of face coverings by wearing one with a presidential seal to Walter Reed medical center and later imploring Americans to wear masks, after resisting wearing one publicly for months.

Trump again wore a mask in publicly while touring a biotech facility in Morrisville Monday afternoon.

White House economic adviser Larry Kudlow spoke to reporters outside the White House wearing a mask for the first time on Monday following a television interview.

“Look, I have been emphasizing masks for a good two weeks, three weeks,” Kudlow said when asked about his face covering. “We are not going to keep the economy open, we’re not going to get the V-shaped recovery, we’re not going to get kids back to school unless we follow simple guidelines – masking, distancing, testing and personal hygiene.”