Newly released internal messages from the authors of a widely cited paper on the origins of Covid-19 are raising fresh questions about how certain the researchers were about the virus's origins.
According to Fox News, Sen. Rand Paul, R-Ky., released Slack messages Tuesday involving Kristian Andersen, Robert Garry, Eddie Holmes and Andrew Rambaut, the authors of "The Proximal Origin of SARS-CoV-2."
The paper, published in Nature Medicine in March 2020, was widely cited by public health officials and media outlets as evidence against the possibility that SARS-CoV-2 originated in a laboratory.
Paul said the newly released communications show the researchers privately considered possibilities that appeared to differ from the paper's public conclusions.
“The idea that it came from a lab is implausible, and, yet, privately they're saying the opposite,” Paul told Fox News. He accused the researchers of dishonesty and questioned whether people who received government research funding should continue to do so.
The messages show that some of the scientists assigned a probability to a laboratory origin. Andersen reportedly placed the likelihood at 30%, while Holmes initially estimated it at 20% before later lowering his assessment to 10%.
In one message from June 2020, Andersen acknowledged uncertainty about the virus's origins and said he had become less confident in the paper's strong language ruling out a laboratory origin.
“The part I’m really struggling with is that, at the end of the day, we really don’t have any hard evidence one way or the other,” Andersen wrote, according to the documents.
The researchers also debated the furin cleavage site, a genetic feature that has become central to discussions surrounding the lab-leak theory.
According to Paul's office, Andersen at one point referred to possible “smoking(ish) guns” and expressed concerns about evidence that made him less confident.
The documents also describe interactions between the researchers and U.S. intelligence officials and National Institutes of Health leadership as the scientists publicly defended their conclusions.
The authors also discussed Ralph Baric, a prominent coronavirus researcher, with internal messages reflecting professional tensions and suspicions that he may have been the anonymous source behind a leak involving confidential peer-review information.
The World Health Organization has previously backed the conclusion that Covid-19 resulted from zoonotic spillover, either directly from bats or through another animal.
Paul, who chairs the Senate Homeland Security and Governmental Affairs Committee, has also subpoenaed Dr. Anthony Fauci to testify this month about the virus's origins.