Federal officials and security companies say they’re seeing less cyberactivity in the run-up to the midterms than than in 2016. But that doesn’t mean officials, voting advocacy groups, and the public aren’t worried.

Fewer than half of Americans surveyed said they’re somewhat or very confident the elections are secure from hacking, according to an Oct. 29 Pew Research Center report. No matter what disruptions might happen on Tuesday, Americans should vote, federal and state officials have said. The loss...