Dr. Anthony Fauci and two other members of the White House coronavirus task force are self-isolating for two weeks after possible exposure to the illness.
Dr. Fauci has become the public face of the fight against the virus in the US.
His agency, the National Institute of Allergy and Infectious Diseases, said he was at “relatively low risk” due to the degree of his exposure.
However, the 79-year-old has tested negative.
Dr. Fauci will work from home for the time being and will be regularly tested, the institute said.
VP Mike Pence’s press secretary Katie Miller, the wife of President Donald Trump’s aide Stephen Miller, tested positive for the virus on May 8.
Katie Miller’s diagnosis came after a valet for President Trump was also confirmed to have the illness.
CDC director Dr. Robert Redfield and FDA commissioner Stephen Hahn are also self-isolating.
In a statement, the CDC said Dr. Redfield, 68, had no symptoms and was not feeling unwell, but would also be working from home for two weeks after “low risk exposure” to someone at the White House. It is unclear who this person is.
An FDA spokesman told Reuters on May 8 that 60-year-old Stephen Hahn was also self-isolating. He has also tested negative, the spokesman said.
The three men were due to address a Senate committee on May 12.
Before the news about Dr. Anthony Fauci became public, committee chairman Senator Lamar Alexander said Dr. Redfield and Dr. Hahn would be allowed to testify by videolink.
The US has 1.3 million confirmed cases and has recorded 78,794 deaths – by far the highest total in the world, according to Johns Hopkins University data.
Many states brought in lockdown measures in March to try to contain the outbreak. But now some have lifted restrictions to allow people to return to work, a move health officials fear could further spread the virus.
Former President Barack Obama has sharply criticized his successor’s response to the crisis. During a private phone call to former staffers, Barack Obama called the response “an absolute chaotic disaster”.
Last week, President Trump said he would refocus the White House task force on kick starting the US economy, a day after suggesting he would disband it.