Biden, 79, still suffers from a sore throat, cough, muscle aches and a runny nose.
The Democrat, who received the full vaccination against COVID-19, is being treated with paxlovid, an anti-covid pill from Pfizer that decreases the ability of the virus to replicate.
Its use is recommended for people at risk of developing a severe case of the disease, a category to which the US president belongs due to his age.
Biden has likely been infected with the highly contagious and dominant BA.5 subvariant of omicron in the country, where it accounts for about 80% of cases, O’Connor said.