President Joe Biden tested negative for COVID-19, his physician announced Saturday. The 79-year-old commander in chief, who was first diagnosed with coronavirus last month, will continue to isolate until he tests negative a second time. “The president continues to feel very well,” Dr. Kevin O’Connor said in a statement released through the White House. “Given his rebound positivity which we reported last Saturday, we have continued daily monitoring. This morning, his SARS-CoV-2 antigen testing was negative.” Biden, who is fully vaccinated and double-boosted, first tested positive for the virus…