He added that Biden would continue to isolate in light of the positive tests.
"He will continue to conduct the business of the American people from the Executive Residence. As I have stated previously, the president continues to b every specifically conscientious to protect any of the Executive Residence, White House, Secret Service and other staff whose duties require any (albeit socially distanced) proximity to him," he said.
Biden first tested positive for COVID-19 on July 21 and suffered mild symptoms including a fever that improved after two full days on antiviral treatment.
He then tested negative on Wednesday, less than a week after the initial positive test and delivered a speech from the White House Rose Garden detailing his recovery and declaring he was no longer in isolation.
Biden tested positive for COVID-19 again on Saturday in what O'Connor described as a "rebound" in which a small percentage of patients treated with Paxlovid can test positive for the virus after having tested negative.
O'Connor noted, however, that Biden was not experiencing any new symptoms and would not need to resume treatment.