From NPR:

CHANG: So what exactly are Bernie Sanders and Joe Biden saying about why they canceled their events today?

FESSLER: Well, their campaigns just announced this this afternoon. They said they will not hold two separate rallies that they had planned tonight in Cleveland and that they were doing that on the advice of Ohio officials. And both Sanders and Biden had said earlier they would seek guidance from health authorities on whether to proceed with these big indoor rallies, whereas, you know, thousands of people are…

CHANG: Yeah.

FESSLER: …Sometimes pushed together and that they’re doing this out of concern for public health. President Trump has said that he still plans to go ahead and hold what he calls, quote, “tremendous rallies.” But that said, he doesn’t have any planned at the moment.

CHANG: Well, even though these campaign events are getting canceled, I mean, voters still need to vote. So what type of precautions are election officials taking at the polling sites?

FESSLER: Well, just about everywhere, it seems, they’re equipping polling sites with hand wipes and disinfectants, and they’re telling poll workers to routinely clean any surface that’s touched by the voters. Some places are even making gloves available for poll workers and voters.

Read the full transcript of the discussion through this link.