Ms Hicks, who is an advisor to the president, reportedly tested positive for the disease on Thursday, the day after she traveled with the president to a rally.
The information was revealed by an anonymous administration official who spoke to the Bloomberg news agency.
According to reports, Ms Hicks is Mr Trump’s closest aide to testing positive for the disease so far.
The 31-year-old has traveled with the president several times over the past week, most notably on the Presidential Marine One helicopter and Air Force One until Tuesday night’s first presidential debate.
There is no indication that Mr Trump has contracted the virus and it is not known whether he has been tested since Ms Hicks was diagnosed.
In a statement, White House spokesman Judd Deere said, “The president takes the health and safety of himself and all who work for him and the American people very seriously. ”
“White House Operations is working with the President’s physician and the White House military office to ensure all plans and procedures incorporate current CDC guidelines and best practices to minimize exposure to COVID-19 both on resorts and when the president is away. , ” he added.
Ms Hicks stepped down as White House communications director in 2018, but returned earlier this year as an adviser, working closely with President’s son-in-law Jared Kushner.