Nearly half of the Twitter accounts spreading messages on the social media platform about the coronavirus pandemic are likely bots, according to researchers.

Carnegie Mellon University researchers said Wednesday that they had examined more than 200 million tweets discussing the virus since January and found that about 45 percent were sent by accounts that behave more like computerized robots than humans.

“We’re seeing up to two times as much bot activity as we’d predicted based on previous natural disasters, crises and elections,” said Kathleen Carley, a professor in the School of Computer Science’s Institute for Software Research, in a statement.

Carley and her colleagues used a bot-hunter tool, which was able to flag accounts that tweet more than is humanly possible or claim to be in multiple countries within a few hours’ period. In order to determine if an account is a bot, they also looked at a Twitter account’s followers, how often it tweets and how frequently the user is mentioned on the platform.

Although it’s not known what individuals or groups are behind the bots, researchers said the tweets appeared aimed at sowing division in America.

“We do know that it looks like it’s a propaganda machine and it definitely matches the Russian and Chinese playbooks, but it would take a tremendous amount of resources to substantiate that,” said Carley, who is conducting a study into bot-generated coronavirus activity on Twitter that has yet to be published.

Among the more than 100 false narratives about COVID-19 that are proliferating on Twitter thanks to accounts controlled by bots: conspiracy theories about hospitals filled with mannequins and conspiracy theories about a connection to 5G wireless towers. Both of these are false.

If users are unsure about an account’s authenticity, they should do their own research to the best of their ability, according to researchers.

“Even if someone appears to be from your community if you don’t know them personally, take a closer look and always go to authoritative or trusted sources for information,” Carley said. “Just be very vigilant.”