Some Minnesota Republicans have started distancing themselves from Anton Lazzaro, pledging to return donations from him.
All four of Minnesota's Republican members of Congress will oppose efforts to impeach President Donald Trump for a second time.
A clerical error left Reps. Jim Hagedorn and Pete Stauber off the list.
Democrat Tawnja Zahradka challenges three-term Rep. Tom Emmer in the heavily Republican district.
Emmer says he has not been exposed to the staffers for several weeks.
The congressmen were exposed to COVID-19 on Air Force One.
U.S. Reps. Pete Stauber, Tom Emmer and Jim Hagedorn flew after being exposed to President Trump and others on Air Force One.
The damage is estimated at over $500 million.
A report says it was sent in his capacity as GOP congressional committee chair.