Yan’s work, which was posted to the scientific research repository Zenodo without any review on Sept. 14, exploded on Twitter, YouTube and far-right websites with the help of such conservative influencers as Republican strategist Stephen K. Bannon, who repeatedly pushed it on his online show “War Room: Pandemic,” according to a report published Friday by Harvard researchers studying media manipulation. Yan expanded her claims, on Oct. 8, to blame the Chinese government explicitly for developing the coronavirus as a “bioweapon.”