LAS VEGAS (AP) — President Joe Biden tested positive for COVID-19 while traveling Wednesday in Las Vegas and is experiencing “mild symptoms” including “general malaise” from the infection, the White House said.

Press secretary Karine Jean-Pierre said Biden will fly to his home in Delaware, where he will “self-isolate and will continue to carry out all of his duties fully during that time." The news had first been shared by Unidos US President and CEO Janet Murguía, who told guests at the group's convention in Las Vegas that president had sent his regrets and could not appear because he tested positive for the virus.

Dr. Kevin O'Connor, the president's physician, said in a note that Biden, 81, “presented this afternoon with upper respiratory symptoms, to include rhinorhea (runny nose) and non-productive cough, with general malaise.” After the positive COVID-19 test, Biden was prescribed the antiviral drug Paxlovid and has taken his first dose, O'Connor said.

Biden was slated to speak at the Unidos event in Las Vegas Wednesday afternoon as part of an effort to rally Hispanic voters ahead of the November election. Instead, he departed for the airport to fly to Delaware, where he had already been planning to spend a long weekend at his home in Rehoboth Beach.

The president's diagnosis comes amid intense scrutiny of his health and stamina after a disastrous debate with former President Donald Trump that sparked a flurry of concern among Democrats that Biden is not up to the rigors of winning another presidential term.

Biden gingerly boarded Air Force One and told reporters traveling with him, “I feel good.” The president was not wearing a mask as he walked onto Air Force One.

The president had previously been at the Original Lindo Michoacan restaurant in Las Vegas, where he was greeting diners and sat for an interview with Univision.

Biden has been vaccinated and is current on his recommended annual booster dose for COVID-19. The vaccines have proven highly effective at limiting serious illness and death from the virus, which killed more than 1 million people in the U.S. since the pandemic began in 2020. Paxlovid has been proven to curtail the chances of serious illness and death from COVID-19 when prescribed in the early days of an infection, but has also been associated with rebound infections, where the virus comes back a few days after clearing up.

Biden last tested positive for COVID-19 twice in the summer of 2022, when he had a primary case and a rebound case of the virus.

Health officials have reported recent upticks in emergency room visits and hospitalizations from COVID-19. There has also been a pronounced increase in positive test results in much of the country — particularly the southwestern U.S.