The number of confirmed U.S. coronavirus cases has begun to rapidly increase in recent days, surpassing 500. One senior administration official said they expected that number to double by Tuesday. Others said they expected a surge in new cases that could strain the administration’s capabilities.

Concerns for the president’s personal health have also escalated as the death toll from the virus has risen, with most of the victims being senior citizens. Trump’s personal doctor, Sean Conley, now attends some White House meetings on the coronavirus, tracking where new cases are being reported, one official said.

The White House is also being cleaned more regularly and people with flu-like symptoms are being urged not to come into the complex, with the added warning that they may infect the leader of the free world, officials said. Changes to Trump’s travel schedule are also being contemplated, after public health officials warned that elderly Americans should reconsider flying on airplanes and avoid large crowds.

Trump, 73, had no campaign rallies scheduled as of Sunday evening, marking the first time this year that there were no such events on the books.