The Pfizer-BioNTech coronavirus vaccine became a target of conspiracy theories and disinformation campaigns as soon as it was announced, reaching millions of people on sites like Twitter, Reddit and 4chan, according to a recent analysis from a cyber defense firm.

COVID-19 conspiracy narratives, like the false belief that the vaccine was delayed for political reasons, flourished on social networks in the fall and early winter, according to the New York tech security firm Blackbird. The firm created an algorithm to analyze posts in real-time by hunting for signals of what CEO Wasim Khaled calls “synthetic amplification,” which indicate activity by botnets and anti-vaccination influencers. 

These bogus notions about the vaccines, amplified by a relatively small number of fake accounts and real influencers, reached millions of people, Khaled said. 

Botnets and inauthentic accounts — automated accounts not actively managed by humans — have behavioral signatures that are easy for AI to identify, but hard for social networks to eradicate. Companies like Facebook and Twitter use both machine-learning algorithms and human moderators to reduce the spread of conspiracies, but Khaled said botnets are effective because they’re inexpensive and easy to deploy.

“Bots and influencers work in tandem,” he explained. “We can’t prove if they collude behind the scenes, but social media data shows clearly that they influence each other by sharing the same links, repeating the same phrases, tagging the same accounts and jumping in on trending hashtags.” 

For example, some botnets reach real influencers by spamming conspiracy links to trending hashtags. Another common tactic is to generate fake trends by synchronizing hundreds of posts using similar anti-vaccine and pseudoscientific claims.