Ms Hicks serves as counsellor to President Trump and is part of his close group of advisors. She tested positive after traveling with Mr Trump on Tuesday to and from the first presidential election debate.
Ms Hicks was also on one of the president’s helicopters on Wednesday.
The helicopter, Marine One, left the White House to fly to Joint Base Andrews in Maryland.
White House spokesperson, Judd Deere, told ABC News: “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.”
There has been no confirmation that President Trump has contracted the virus.
The coronavirus has infected more than 7.2million Americans bringing over 200,000 deaths related to the disease in the US.
Other members of President Trump’s staff have previously contracted the virus.
Mr Trump’s National Security adviser, Robert O’Brien, tested positive for COVID-19 in July.
Ms Hicks was seen on Tuesday not wearing a mask while in a staff van with White House senior adviser Stephen Miller and campaign adviser Jason Miller.
On their return to the White House on Tuesday, Mr Miller and Ms Hicks were seen sharing an umbrella when they left the Air Force One plane in the rain.
Mr Miller’s wife Kate, who is vice-president Mike Pence’s press secretary, recovered from the coronavirus earlier this year.
Ms Hicks was seen wearing a mask while traveling on board the presidential helicopter, Marine One, this week.
President Trump is regularly tested for the coronavirus, but it is not known how often.
People who work in the White House are tested daily for the virus, as well as members of the press and anyone else who visits.
More to follow.