"His symptoms have been steadily improving, and are almost completely resolved," the physician, Kevin O'Connor, said in a statement, noting that the president tested negative by antigen testing Tuesday evening and Wednesday morning.

Biden was the second sitting US president to be infected with the virus following his predecessor Donald Trump.

Having ended his five-day course of the antiviral drug Paxlovid, Biden remains fever-free and has not taken Tylenol, a fever reducer and pain reliever, for the past 36 hours.

In coming out of isolation, Biden will continue to wear a mask whenever he is around others for a period of 10 days, the physician said.

Citing the potential for so-called rebound COVID-19 positivity seen in some patients treated with Paxlovid, O'Connor said the president will increase his testing frequency to assure early detection of any return of viral replication.

Biden tested positive last Thursday and has been experiencing mild symptoms. He was found to have been most likely infected with the highly transmissible BA.5 subvariant of Omicron, which has been spreading in the United States.

Trump, then 74, contracted the virus about a month before the 2020 presidential election and was hospitalized for three nights. At the time, there were no COVID-19 vaccines authorized for use.

Biden has been fully vaccinated and has received two booster shots for additional protection.