Hope Hicks, one of President Donald Trump’s closest aides, has tested positive for the coronavirus.

Hicks, who serves as counselor to the president and traveled with him to a rally Wednesday, tested positive Thursday, according to an administration official, who spoke on condition of anonymity to discuss private health information. She is the closest aide to Trump to test positive so far.

The White House did not immediately respond to multiple questions about the last time Trump was tested and whether he and other staffers who spent time with Hicks in recent days will be asked to quarantine.

Click here for full Covid-19 coverage

Trump traveled Thursday to New Jersey for a fundraiser. His social media director Dan Scavino and press secretary Kayleigh McEnany were originally set to join him, but were replaced at the last minute by other aides.

In a statement, White House spokesman Judd Deere said, “The President takes the health and safety of himself and everyone who works in support of him and the American people very seriously.”

“White House Operations collaborates with the Physician to the President and the White House Military Office to ensure all plans and procedures incorporate current CDC guidance and best practices for limiting Covid-19 exposure to the greatest extent possible both on complex and when the President is traveling,” Deere said.

Hicks traveled with the president multiple times this week, including aboard Marine One, the presidential helicopter, to a rally in Minnesota Wednesday, and aboard Air Force One to Tuesday night’s first presidential debate.

Hicks, one of the president’s most trusted aides, previously served as White House communications director and rejoined the administration this year ahead of the election. Her positive test was first reported by Bloomberg News.

Multiple White House staffers have tested positive for the virus, including Katie Miller, Vice President Mike Pence’s press secretary, national security adviser Robert O’Brien, and one of the president’s personal valets.

After earlier positive cases close to the president, the White House instituted a daily testing regimen for the president’s senior aides. Others who will be in close proximity to the president and vice president, including reporters, are also tested every day.

While the Centers for Disease Control and Prevention recommends that people who have been in close contact with someone with Covid-19 quarantine for 14 days, White House staffers are considered essential workers. CDC’s guidelines for exposed essential workers allows them to return to work if they take precautions, including taking their temperature before going into work, wearing a mask at all times and practicing social distancing.

Trump, the White House and his campaign have flouted other CDC guidelines and recommendations from public health officials, and largely refused to wear masks or practice social distancing.