Announcing his Covid infection on Wednesday night, the White House said the 81-year-old was facing mild symptoms.

Karine Jean-Pierre, his press secretary, said the president was vaccinated and boosted. He has tested positive for Covid twice before.

Mr Biden was seen earlier in the day visiting supporters in Las Vegas and speaking at an event. He cancelled a campaign speech later in the night.

Ms Jean-Pierre said the president planned to isolate at his home in Delaware while carrying out “all of his duties fully”.

The president’s doctor, Kevin O’Connor, said Mr Biden had presented with upper respiratory symptoms, including a runny nose and a cough, and had been given his first dose of Paxlovid.

He felt fine during his first event of the day but later tested positive, Dr O’Connor said.

Mr Biden later used X/Twitter to thank everyone for “the well wishes” and said he would “work to get the job done for the American people” while in recovery.

In another tweet his account stated “I’m sick” before replying back “… of Elon Musk and his rich buddies trying to buy this election. And if you agree, pitch in here”.