It turns out twitter bots aren’t just being employed by foreign agents to sway public political opinion. A new piece of research from George Washington University shows that social media bots and Russian trolls have also been used to spread false information about vaccines on Twitter. The paper entitled Weaponized Health Communication details how, using similar tactics to those in the lead up to the U.S. 2016 general election, fake news and conspiracy theories were employed to amplify anti-vaccine sentiments.

It transpires that the very same accounts, termed “content polluters,” that were found to be interfering with the last U.S. election were also 75 percent more active on questioning the safety of vaccines, bringing into question well established general public health policies. The conclusion being that Russian trolls latched on to the divisive issue to induce political discord during run-ups to major US democratic events. “These trolls seem to be using vaccination as a wedge issue, promoting discord in American society,” said Mark Dredze, a team member and professor of computer science at Johns Hopkins. “However, by playing both sides, they erode public trust in vaccination, exposing us all to the risk of infectious diseases. Viruses don’t respect national boundaries.”

Researchers reviewed more than 250 tweets about vaccination sent by accounts linked to the Internet Research Agency, the Russian government-backed company recently indicted by a U.S. grand jury because of its attempts to interfere in the 2016 elections, finding that the tweets used polarizing language linking vaccination to controversial issues in American society, such as racial and economic disparities.

“The vast majority of Americans believe vaccines are safe and effective, but looking at Twitter gives the impression that there is a lot of debate. It turns out that many anti-vaccine tweets come from accounts whose provenance is unclear. These might be bots, human users or “cyborgs”—hacked accounts that are sometimes taken over by bots. Although it’s impossible to know exactly how many tweets were generated by bots and trolls, our findings suggest that a significant portion of the online discourse about vaccines may be generated by malicious actors with a range of hidden agendas,” said David Broniatowski, an assistant professor in GW’s School of Engineering and Applied Science.

The news comes as cases of measles in the U.S. are on the rise, facing an uptick since the disease was found to be in decline in 2014. Despite the fact that a vaccine has been available for the past 50 years, the highly contagious virus crept back after the now discredited British doctor Andrew Wakefield falsely claimed a relationship between the MMR jab and autism. Admired by many Trump supporters, earlier this year Wakefield entered back into the public eye after being photographed with Elle Macpherson.