Three senior officials guiding the US response to the coronavirus pandemic were in self-quarantine on Saturday after coming in contact with someone who had tested positive for the disease, their agencies and spokespersons said.

Anthony Fauci, a high-profile member of the White House coronavirus response team, is considered to be at relatively low risk based on the degree of his exposure, according to a representative for the National Institute of Allergy and Infectious Diseases.

Fauci, the 79-year-old director of that institute, has tested negative for Covid-19 and he will continue to be tested regularly, the official said in an emailed statement.

Robert Redfield, director of the Centres for Disease Control and Prevention (CDC), “will be teleworking for the next two weeks” after a “low-risk exposure” on Wednesday to a person at the White House who has the disease, the CDC said in a statement. Redfield is 68 years old. He is “feeling fine” and has no symptoms, the statement added.

If required to go to the White House, Redfield will follow the CDC’s safety practices like taking temperature, screening for symptoms each day, wearing a face covering, and distancing, the CDC said.

US Food and Drug Administration (FDA) commissioner Stephen Hahn, who is 60, is also in self-quarantine for a couple of weeks after coming in contact with someone who tested positive for the illness, an FDA spokesman told Reuters late on Friday.

Hahn immediately took a diagnostic test for the coronavirus and the results were negative, FDA spokesman Michael Felberbaum said in an emailed statement.