Sanders taking coronavirus 'very seriously' on campaign trail

"We take the coronavirus seriously as you know... What we are doing, wherever we go, whenever we do rallies, we consult with public health officials because the last thing in the world is that we would ever want to do is put anyone in danger, " Sanders said.

With 125 delegates, Michigan is the biggest prize of the six states voting on Tuesday, when a total of 352 delegates to July's Democratic nominating convention will be up for grabs.

Missouri, Mississippi, Washington, North Dakota and Idaho also hold nominating contests.