In the latest twist in the ongoing story of Russian interference in the US presidential elections of 2016, it has emerged that Russian internet trolls and automated bots spread misinformation about vaccines on Twitter to stir up division in the US.

Researchers at George Washington University, while working on a project to improve social media communications for public health workers, discovered several accounts – now known to belong to the same Russian trolls who interfered in the US election – as well as marketing and malware bots, tweeting about vaccines and attempting to skew online debate and shift consensus about vaccine safety.

This trolling has had an impact on both the political and health sphere according to the researchers. Furthermore, the trolls played both sides of the debate in what was a politically charged context; tweeting pro- and anti-vaccine content. Mark Dredze of Johns Hopkins University, which was also involved in study, posited that “These trolls seem to be using vaccination as a wedge issue, promoting discord in American society. By playing both sides, they erode public trust in vaccination, exposing us all to the risk of infectious diseases.”

The tweets appeared to link vaccination to hot-button issues such as race, class, religion and animal welfare, often targeting the legitimacy of the US government. One sample tweet read, “Did you know there was secret government database of #Vaccine-damaged child? #VaccinateUS,” Another said: “#VaccinateUS You can’t fix stupidity. Let them die from measles, and I’m for #vaccination!”

The researchers concluded that “Whereas bots that spread malware and unsolicited content disseminated anti-vaccine messages, Russian trolls promoted discord. Accounts masquerading as legitimate users create false equivalency, eroding public consensus on vaccination.”

David Broniatowski, assistant professor at George Washington’s School of Engineering and Applied Science, added that “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.” Broniatowski also noted that “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.”

This latest news comes at a time when knowledge of the importance and necessity of vaccination appears to be on the wane. The rate of children not being given vaccines for non-medical reasons has climbed significantly in the US and Europe is facing one of the most serious measles outbreaks in decades; an outbreak at least partly attributed to falling vaccination rates.