“The President continues to feel good,” Dr. Kevin O’Connor wrote. “In light of the positive rebound we reported on him last Saturday, we continue to conduct daily monitoring. This morning, he tested negative for the SARS-CoV-2 antigen. Out of an abundance of caution, the President will continue with strict quarantine measures, pending The second negative test was as previously described.”
According to the U.S. Centers for Disease Control and Prevention, “people who have a recurrence of COVID-19 symptoms or who test negative for the virus and who test positive for the virus should resume isolation and quarantine again for at least 5 days.”
The CDC issued a health alert to doctors on May 24, advising that Covid-19 symptoms sometimes recur, which may be how some people become infected, regardless of whether they were vaccinated or treated with drugs such as Paxlovid. The CDC said most of the rebound cases involved mild illness, and there were no reports of serious illness.
Biden has been fully vaccinated and received two booster shots. He received the first two doses of the Pfizer/BioNTech Covid-19 vaccine before taking office in January 2021, the first booster in September and the second in March.
This story has been updated.