The Pennsylvania Department of Health is encouraging people who were at President Donald Trump’s campaign rally at Harrisburg International Airport on Saturday to get tested if they are feeling sick.

Trump announced earlier Friday that he and the first lady have tested positive for the coronavirus.

The department is asking people to download the COVID Alert PA phone app if they do test positive to anonymously alert people they may have come in contact with.

Thousands attended the outdoor rally, held hours after the president introduced his Supreme Court nominee, Amy Coney Barrett, from the Rose Garden at the White House. Those at the rally were required to pass through a security checkpoint and get their temperatures taken.

The president had another rally in the last week, on Wednesday in Duluth, Minnesota.

Three Republicans boarded Air Force One in the Twin Cities and flew with the president to the Duluth rally location. Two of them, Congressman Tom Emmer and Congressman Jim Hagedorn, told local media they are taking a COVID-19 test after possible exposure to the president or a member of his team.

Other lawmakers who interacted with the president while he stopped at Twin Cities International Airport have taken steps to protect their health, according to KARE11.