The news was first revealed by Janet Murguia, the chief executive of UnidosUS, who said Mr Biden would no longer appear at the group’s conference in Las Vegas.
“I was just on the phone with President Biden. And he shared his deep disappointment at not being able to join us this afternoon. The president has been at many events as we all know and he just tested positive for Covid,” she told conference attendees.
Biden will take Paxlovid
Dr O’Connor said Mr Biden had already received his first dose of Paxlovid, an antiviral drug used to treat Covid.
Mr Biden has been vaccinated, but his age means he is at a higher risk of serious complications from the virus.
The number of deaths among people over age 65 is 97 times higher than the number of deaths among people ages 18-29 years, according to the US Centres for Disease Control and Prevention.
Mr Biden has faced weeks of questions about his health, after his stuttering performance in the debate last month.
The White House has denied that he has Parkinson’s disease or any medical condition that would prevent him from serving as president. Mr Biden himself has said that he intends to hold fewer public events after 8pm to ensure he rests enough during the campaign.
Earlier on Wednesday, Mr Biden told a Black Entertainment Television reporter that he would step down from the 2024 election race if he was diagnosed with a serious medical condition. He had previously said only the “Lord Almighty” could convince him to give up the Democratic nomination.