Originally Published: 15 JUN 22 14:53 ET

Updated: 15 JUN 22 15:27 ET

By Jamie Gumbrecht and Jen Christensen, CNN

(CNN) -- Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and President Biden's chief medical adviser, has tested positive for Covid-19, the institute said Wednesday.

Fauci, 81, has mild symptoms and has been boosted twice, the institute said in a statement.

NIAID said Fauci found out that he was positive on a rapid antigen test. The director will work from home and follow agency protocol, returning to the National Institutes of Health campus only after he tests negative.

Fauci has not had any close contact with Biden or other senior officials recently, the institute said.

Throughout the pandemic, he has urged caution and has demonstrated it himself at public events. For instance, he chose not to attend the annual White House Correspondents' Dinner in April after considering his individual risk.

"Each of us, in our own personal way, has to make an assessment of what risk you're willing to accept about getting infected," he told CNN. "In general, the risk is low, but I made a personal assessment. I'm 81 years old, and if I get infected, I have a much higher risk."

Fauci has been working nonstop during the pandemic. In May, he said he hadn't had a day off since Covid-19 came to the US.

He has been the director of NIAID since 1984 and has advised seven Presidents.

Fauci joins a growing list of Biden administration leaders who have had Covid-19, including White House domestic policy adviser Susan Rice, Attorney General Merrick Garland, Vice President Kamala Harris and Commerce Secretary Gina Raimondo.

This is a breaking news story and will be updated.