YouTube announced a sweeping crackdown of vaccine misinformation Wednesday that booted popular anti-vaccine influencers from its site and deleted false claims that have been made about a range of immunizations.

The video-sharing platform said it will no longer allow users to baselessly speculate that approved vaccines, like the ones given to prevent the flu or measles, are dangerous or cause diseases.

YouTube's latest attempt to stem a tide of vaccine misinformation comes as countries around the globe struggle to convince a somewhat vaccine hesitant public to accept the free immunizations that...