Biden, 79, first tested positive for the coronavirus on July 21, a Thursday, and started taking Paxlovid, an antiviral therapy that has been shown to be very effective in fighting coronavirus symptoms. After the president’s initial positive test result, O’Connor said Biden — who is fully vaccinated against the coronavirus and received two booster shots — should respond well to Paxlovid, “as most maximally protected patients do. “.
After a daily check, Biden tested negative the following Tuesday evening. He emerged from his Covid-19 isolation last Wednesday with a speech at the Rose Garden touting his relatively short isolation and mild symptoms as a testament to his administration’s progress on the pandemic. He urged people to also take advantage of vaccine boosters, antivirals and home testing.
Biden tested negative last Wednesday morning, Thursday morning and Friday morning, before testing positive again Saturday morning using an antigen test. Biden and his doctor said he had no symptoms during the rebound infection.
What to know about rebound cases after Paxlovid treatments
Biden took off his mask for some of the events last week. White House press secretary Karine Jean-Pierre said Biden still complied with Centers for Disease Control and Prevention guidelines because he was more than six feet from others.
The CDC recommends people self-isolate for five days after testing positive for the coronavirus and wear a mask for an additional five days when around other people. Some experts have said the guidelines could cause people to return to work or leave isolation while potentially still infectious.
Doctors have warned that people who receive the antiviral drug Paxlovid can experience ‘rebound’ infections within days of initially testing negative, although data on the frequency of the event and its long-term effects remain unclear.
Initial clinical studies suggested that only 1-2% of people treated with Paxlovid experienced symptoms again, but another study published in June reported that 6% experienced symptoms again. Studies are ongoing to determine if longer treatment with Paxlovid can help prevent cases of rebound.
The CDC issued an advisory in May amid concerns over the phenomenon, recommending people who experience a resurgence of covid-19 after treatment to self-isolate again for five days and wear a mask for 10 days.
The CDC recommends that the public report cases of rebound after a course of Paxlovid to Pfizer, the drug’s maker.
In his Sunday memo, O’Connor wrote that Biden would continue his “strict isolation measures.”
Biden canceled planned trips to his home in Wilmington, Del., on Sunday and to Hemlock, Michigan, on Tuesday for an event in support of a bill that includes $52 billion to subsidize the manufacturing and research of computer chips and countering the influence of China, known as the Chips and Science Act. The legislation passed both houses of Congress this week and is awaiting Biden’s signature. It was unclear whether Biden would participate in Tuesday’s event remotely.
Bryan Pietsch contributed to this report.