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(The Hill) – President Biden feels well enough to start exercising again on his fifth day of isolation after contracting COVID-19, his physician, Kevin O’Connor, said in a new memo released on Tuesday.  

O’Connor wrote that Biden’s symptoms “have now almost completely resolved” after the president completed his five-day course of Paxlovid, an antiviral pill used to treat the novel coronavirus.  

“His symptoms have now almost completely resolved. His pulse, blood pressure, respiratory rate and temperature remain absolutely normal. His oxygen saturation continues to be excellent on room air. His lungs remain clear,” O’Connor wrote in the new update. “The President now feels well enough to resume his physical exercise regimen.” 

The letter did not specify what kind of physical exercise, but Biden is known to enjoy riding a stationary bike.

Biden is expected to remain in isolation in the White House residence until at least Wednesday.  

White House COVID-19 response coordinator Ashish Jha told reporters on Monday that Biden would resume in-person work once he tests negative for COVID-19 after the five-day window.

Centers for Disease Control and Prevention guidelines say that COVID-19 patients can stop isolating after five days if they do not show symptoms or their symptoms are improving.

Biden has shown mild symptoms since he tested positive for the virus on Thursday, according to White House officials, such as fatigue and a cough. He has continued to work throughout his illness, appearing at a virtual meeting on semiconductor legislation on Monday afternoon. 

Biden told reporters then that he still had a sore throat but that he hoped to return to work in person by the end of the week.  

“I’m feeling great,” he said. “I think I’m on my way to full, total recovery, God willing.” 

O’Connor has provided daily written updates on the president’s health since last Thursday, but the White House has declined to make him available to the press to answer questions. Instead, Jha and White House press secretary Karine Jean-Pierre have fielded questions at the daily briefing about the president’s progress.

Biden, 79, is considered vulnerable to COVID-19 due to his age, but health experts have been optimistic about his case because he is up to date with his vaccinations and taking Paxlovid.  

Still, experts note it’s possible that Biden could experience “rebound” symptoms, as some patients who have used Paxlovid have.

Jha told reporters Monday that clinical data suggests between 5 and 8 percent of patients experience rebound following Paxlovid treatment, and that symptoms could return after 3 or 4 days if not longer.  

“We will continue monitoring … the president on an ongoing basis,” Jha said.