photo by: Associated Press

U.S. Rep. Roger Marshall, R-Kan., talks to the crowd in front of photo of Supreme Court nominee Amy Coney Barrett while attending a Concerned Women for America event outside a gun store in Kansas City, Kan. Wednesday, Oct. 21, 2020. (AP Photo/Charlie Riedel)

TOPEKA (AP) — A staffer on Republican Roger Marshall’s campaign for an open U.S. Senate seat in Kansas has tested positive for the coronavirus.

Marshall’s campaign confirmed Tuesday that the staffer tested positive last week after experiencing mild symptoms and self-quarantining. Marshall chief of staff Brent Robertson said in a statement that the unnamed staffer was exposed to the virus at a “personal” event and hasn’t had contact with the candidate Marshall since before that event.

Marshall’s comments and actions during the coronavirus pandemic have become a major issue in his race against Democrat Barbara Bollier.

He was a long-time obstetrician before he began representing a central and western Kansas district in Congress in 2017, and she is a retired anesthesiologist and Kansas City-area state senator. He has said during campaign stops that the U.S. is making progress in containing COVID-19 and he has sometimes appeared before unmasked supporters. Bollier has accused him of ignoring science.

“Out of an abundance of caution, Dr. Marshall regularly tests and continues to be negative,” Robertson said.

Bollier spokeswoman Alexandra De Luca told The Kansas City Star that Bollier will get tested quickly because she and Marshall had a debate last week. She called on The Marshall campaign to release more information.