Facebook has removed hundreds of fake accounts linked to a campaign by China to spread unfounded claims about the pandemic.
The bogus profiles originated claims the US pressured scientists to blame China for COVID-19.
An investigation found these claims were amplified by employees of Chinese state-run companies, soon becoming the subject of domestic news headlines.
“In effect it worked like an online hall of mirrors, endlessly reflecting the original fake persona and its anti-US disinformation,” Ben Nimmo, who leads investigations into disinformation at Meta, the parent company of Facebook and Instagram, said.
The social media company said one of the accounts belonged to a fictitious Swiss biologist named Wilson Edwards.
In July, when the operation began, Mr Wilson’s profile claimed US officials were using “enormous pressure and even intimidation” to get scientists to back calls for renewed investigations into the origin of coronavirus.
Within hours, hundreds of other accounts – some only created only that day – began liking, reposting or linking to the post.
Many of the accounts were later found to be fake, with some of the users posing as westerners and others using likely fabricated profile photos.
Facebook said it found links between the accounts and a tech firm based in Chengdu, China, as well as to overseas employees of Chinese infrastructure companies.
Within a week of the initial post, large media outlets in China were reporting on the claims as if they had been made by a real scientist.
The operation was exposed when Swiss authorities announced in August that they had no record of any biologist with that name.
In all, Meta removed about 600 accounts on Facebook and Instagram that were linked to the network.
China’s Ministry of Foreign Affairs has said in the past that the country’s government does not employ trickery on social media.
Coronavirus emerged in Wuhan, China in December 2019 before spreading around the world.
Different governments, experts and organisations, including the US, have suggested the virus may have come from a lab leak in the city – a claim China vehemently denies.
That theory was dismissed by a team led by the World Health Organisation (WHO) that spent four weeks in and around Wuhan in January and February.
However, their report, released in March, was criticised for not finding sufficient evidence to discard the idea – and the WHO’s director-general has since said there had been a “premature push” to rule out the lab leak theory.
The US carried out their own investigation and came to the same conclusion.