U.S. President Joe Biden continued to test positive for COVID-19 on Tuesday in what doctors described as a "rebound" case of the virus.
The President's physician, Dr. Kevin O'Conner, wrote in a White House memo that the president's "loose cough" has returned, though "his temperature, pulse, blood pressure, respiratory rate and oxygen saturation remain entirely normal."
"He remains fever-free and in good spirits," O'Conner said.
Biden, 79, first tested positive for COVID-19 in late July and was cleared from isolation last Wednesday after taking the antiviral drug Paxlovid for several days. He returned to isolation after testing positive again on Saturday.
Rebound cases occur in a small percentage of patients who take the standard five-day course of Paxlovid, a pill produced by Pfizer and authorized to treat high-risk patients. Most rebound cases involve only mild illness, according to the Centers for Disease Control and Prevention, and there have been no reports of serious complications.
White House Press Secretary Karine Jean-Pierre told reporters on Monday that the president may still be experiencing symptoms from his first COVID infection, saying, "Those minimal symptoms kind of linger for some time, so you can expect that."
During his first COVID-19 infection, Biden's symptoms included a runny nose, fatigue, high temperature and a cough. O'Connor wrote in his Saturday memo that Biden was not symptomatic, but he did not say whether Biden was experiencing symptoms in his Sunday and Monday memos.
Since re-testing positive, Biden has had to cancel a trip to Michigan and one to his home in Delaware. On Monday evening, he gave an address to a small pool of reporters from a distance on the killing of al-Qaida leader Ayman al-Zawahiri.
Some information from this report came from Reuters and CNN.