Biden Still Positive for COVID-19 as He Deals With Pfizer Drug ‘Rebound’: Doctor

President Joe Biden again tested positive for COVID-19 on Monday due to a “rebound” of “positivity” sparked by the drug Paxlovid, according to his doctor in an update.

Biden, 79, tested positive on Monday morning for the third day in a row, White House physician Kevin O’Connor wrote in a letter (pdf) to press secretary Karine Jean-Pierre. Last week, he returned a negative COVID-19 test as he was taking Paxlovid, which is known to cause a recurrence of symptoms after a negative test.

“Given his rebound positivity, which we reported Saturday, we continued daily monitoring,” he said. “This morning, as could be anticipated, his SARS-CoV-2 antigen testing remained positive.”

Biden, who has received four vaccine doses, will continue to be under strict isolation for the time being, O’Connor said.

“He will continue to conduct the business of the American people from the executive residence,” O’Connor said in the daily memo. The doctor said Biden’s symptoms have not returned despite the COVID-19 positivity.

Last week, the president briefly emerged from quarantine following a negative test, delivering remarks at the White House Rose Garden. The White House has not confirmed whether any staffers contracted COVID-19.

Per Centers for Disease Control and Prevention (CDC) guidelines, Biden has to quarantine for at least five days after testing positive for the virus.

Over the weekend, the White House told reporters via the press pool that Biden will not embark on a scheduled trip to Saginaw County, Michigan. It’s not clear whether the trip will be rescheduled.

COVID Rebound

Health officials and Pfizer have said Paxlovid rebound impacts a small number of recipients, although White House adviser Anthony Fauci also experienced it several weeks ago. Fauci confirmed that he tested negative for four days before testing positive as he took the drug, which was first handed an emergency