Who amplified the vaccine debate?
A 2018 study found Russian-troll accounts posting both for and against vaccines on Twitter in 2014–2017. It shows how some accounts helped spread the debate, not whether vaccines are safe.
This study covered English-language Twitter from July 2014 to September 2017, before COVID.
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Accounts posted opposing messages
Researchers examined about 1.79 million tweets, plus 253 messages using #VaccinateUS. Accounts identified as Russian trolls posted on both sides of the vaccine debate. In the small hashtag sample, 43% of messages favored vaccination, 38% opposed it and 19% were neutral. These are percentages of those messages, not of the public.
Posting is not the same as persuading
Researchers used existing lists and account classifications to identify account types. The study did not establish who ran every unknown account or whether the messages changed people’s beliefs or vaccination choices.
A message still needs to be checked
An organized campaign can share a true report, a real concern or a false claim. Medical evidence still answers vaccine-safety questions. This pre-COVID study cannot tell us where COVID claims began. It does not make ordinary people who discuss vaccines foreign agents.
Check what the message says and who helped spread it as separate questions.
Keep in mind
- This is one historical Twitter study, not a count of all foreign influence or all vaccine discussion today.
- It shows observed posting, not a measured effect on vaccination or beliefs.
- Researchers depended on account lists they did not create themselves.
Spreading a debate is different from starting it
People can exploit disagreements that already exist.
A foreign-linked account sharing a viewpoint does not show that the viewpoint began abroad. Evidence about who ran an account, what they intended, whether a statement was true and whether anyone was persuaded answers different questions.
Sources you can check
Publication links open in a new tab, so you can keep your place here.
Weaponized Health Communication: Twitter Bots and Russian Trolls Amplify the Vaccine Debate (opens in a new tab)
American Journal of Public Health, 2018
It covers July 2014–September 2017. Researchers relied on account lists and classifications. It did not measure changed vaccination choices and cannot establish where COVID claims began.
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Detailed research notes and source data
Our longer notes explain how we checked the studies, including disagreements and documents we could not get.
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Research checked: . Wording reviewed: 2026-10-07. Version: draft-3.
We revisit the page when new evidence or corrections change the answer. A public history of corrections is not available yet.