Bots and Russian trolls spread false information about vaccines on Twitter in order to sow discord and propagate malicious content prior to and during the 2016 U.S. presidential election, according to a new study.
Scientists made the discovery while researching how social media communications for public health workers could be improved.
According to researchers, Russian trolls played from both sides, tweeting pro- and anti-vaccine content.
“These trolls seem to be using vaccination as a wedge issue, promoting discord in American society,” Mark Dredze, a team member and professor of computer science at Johns Hopkins, which was involved in the study, told the Guardian.
In tweeting both pro- and anti-vaccine information, the Russian trolls are able to erode public trust in vaccination across borders.
The study was published in the American Journal of Public Health and comes as Europe is facing a major outbreak of measles, which has been partly attributed to falling vaccination rates.
There were 41,000 cases of measles across Europe in the first half of 2018, more than in all of 2017, the British publication reports.
“The vast majority of Americans believe vaccines are safe and effective, but looking at Twitter gives the impression that there is a lot to debate,” David Broniatowsky, an assistant professor in George Washington’s School of Engineering and Applied Science, said.
The trolls reportedly tried to link vaccination to other issues in the U.S., like race and religion, and even targeted the legitimacy of the government.
“Accounts masquerading as legitimate users create false equivalency, eroding public consensus on vaccination,” researchers concluded.
Scientists examined a random sample of 1.7 million tweets collected between July 2014 and September 2017, which was a crucial time during the presidential campaign. In order to identify bots, they compared the rate at which regular users tweeted about vaccines with the rate at which bots and trolls do.
Broniatowski told the Guardian that bots tweeted about vaccines about once every 550 tweets, versus once every 12,000 tweets for human accounts.
Social media companies continued to face a backlash over their handling of fake accounts and misinformation. Both Twitter and Facebook have removed accounts linked to the Internet Research Agency, a so-called troll farm connected to the Russian government. Last week, Facebook removed another 650 accounts linked to Russia and Iran that were spreading misinformation.