In a video posted to Twitter, Biden told Americans that he is "doing well" and that his symptoms continue to be mild.

"I guess you heard, this morning I tested positive for Covid. But I've been double vaccinated, double boosted. Symptoms are mild and I really appreciate your inquires and concerns. But I'm doing well, getting a lot of work done. Going to continue to get it done and in the meantime, thanks for your concern and keep the faith. It's gonna be OK," Biden, who was unmasked while standing outside on the Truman Balcony, said in the 20-second video the White House says was filmed by a masked and socially distanced videographer.

The mild symptoms and diagnosis protocol for Biden -- a double-boosted 79-year-old at high risk for experiencing severe illness -- will mean isolating and "working and resting" at the White House residence for the rest of the day, according to a senior administration official. This is the first time Biden has tested positive for Covid-19, and he last tested negative on Tuesday, per White House press secretary Karine Jean-Pierre.

Biden has called several people in the hours since his diagnosis. He wrote on Twitter Thursday afternoon that he is "doing great" following the positive test and said he called Pennsylvania politicians to send his regrets about having to cancel a scheduled trip to the commonwealth.

The tweet was accompanied by an image of the President smiling at a desk, without a mask, in the residence of the White House.