Study finds 93% of tweets about vaccines between 2014 and 2017 were planted with aim of sowing division

Bots and Russian trolls spread misinformation about vaccines on Twitter to sow division and distribute malicious content before and during the American presidential election, according to a new study.

Scientists at George Washington University, in Washington DC, made the discovery while trying to improve social media communications for public health workers, researchers said. Instead, they found trolls and bots skewing online debate and upending consensus about vaccine safety.