The anti-vaccination movement might be getting a boost from Twitter bots and Russian trolls, suggests a new study published Aug. 23 in the American Journal of Public Health. It found that certain kinds of bot accounts were more likely to send antivax tweets than were accounts belonging to actual people, while alleged troll accounts were more likely to stoke the flames of controversy by promoting both pro- and anti-vaccination messages.
The researchers behind this study, led by David Broniatowski of George Washington University in DC, were initially hoping to use Twitter for good. They wanted to see if people’s tweets could be an accurate proxy for surveys that try to determine the public’s overall attitude toward vaccination. These surveys are essential, but relying on social media might allow scientists to more quickly and cheaply track changing public sentiment.
But as they started to sift through vaccine-related tweets, they ran into a problem. The vast majority of people, judging by large, nationally representative surveys, correctly believe that vaccines are safe and essential (the flu shot alone prevents thousands of deaths annually). But Twitter seemed to be swarming with antivaxxers and their false and misleading arguments. Theorizing at least some of this chatter could be the work of bots and other not-so-genuine actors, they decided to compare how different types of accounts talked about vaccines.
Broniatowski and his team looked at thousands of vaccine-related tweets from 2014 to 2017 made by Twitter users, as well as a random sample of 1% of all tweets made during the same time. They then used an algorithm that predicted whether an account was likely to be a human or a bot. They also compared these accounts to ones alleged to be linked to Russian troll farms like the Internet Research Agency.
Likely human accounts rarely talked about vaccines, but when they did, they were usually pro-vaccine. Troll accounts and more sophisticated bot accounts (meaning those that don’t simply send out incoherent gibberish), on the other hand, talked about vaccines more. And content polluters, bots that spew out links to malware and clickbait, more often spouted anti-vaccine tweets.
Russian trolls, meanwhile, were more insidious. They had an equal mix of positive and negative vaccine-related tweets, often using popular hashtags circulated by antivaxxers. “Pharmacy companies want to develop #vaccines to cash, not to prevent deaths #VaccinateUS,” read one of these tweets collected by the team.
The team’s findings aren’t the first to suggest that bots are spreading propaganda about vaccines and other controversial topics. And as much as we try to ignore spammy-looking messages when we come across them, Broniatowski says they could have a real influence on our perceptions of vaccine safety.
