US media reports citing the White House say President Joe Biden tested positive for Covid-19 during a visit to Las Vegas on Wednesday and is self-isolating after mild symptoms.

Business standard (BS) reports that White House press secretary Karine Jean-Pierre announced the positive test for the 81-year-old Democrat after Biden canceled a speech due to the diagnosis.

“He is vaccinated and strengthened and has mild symptoms,” Jean-Pierre said.

The White House said Biden planned to spend the long weekend at his beach house in Delaware. It was unclear how long the illness would keep him on the campaign trail.

The illness comes at a crucial time for Biden, who is losing ground in battleground states against Republican Donald Trump, who is heading a triumphant rally this week after surviving an assassination attempt on Saturday.

CNN says it’s unclear where and when the president contracted Covid-19. But the sudden diagnosis puts him behind closed doors at a time when democratic countries have been clamoring to see him out.

Despite Biden’s diagnosis, Vice President Kamala Harris was scheduled to go ahead with her appearance at a campaign event in Fayetteville, North Carolina on Thursday, according to CNN.

CNN reports that according to a statement from President Biden’s doctor, Biden received several booster doses of the Covid-19 vaccine, most recently in September 2023.

According to the Centers for Disease Control and Prevention (CDC), levels of Covid-19 have increased across the country in recent weeks. The latest figures are said to show a 23.5% increase in emergency visits due to Covid-19 in the week ending July 6 compared to the previous week. The CDC also reports that the level of Covid-19 viral activity in wastewater is high nationally as of July 6.