David Klepper | The Associated Press

Twitter will no longer enforce its policy against Covid-19 misinformation, raising concerns among public health experts and social-media researchers that the change could have serious consequences if it discourages vaccination and other efforts to combat the still-spreading virus.

Voters casting ballots in Tuesday’s pivotal midterms grappled with misleading claims about glitchy election machines and delayed results, the final crest of a wave of misinformation that’s expected to linger long after the last votes are tallied.