An American researcher says files that could shed more light on the origins of COVID-19 were mysteriously deleted from a database last year. Seattle virologist Jesse Bloom says genetic sequences from more than 200 early COVID cases in Wuhan were submitted to an online database by Chinese researchers in March 2020 and removed at their request in June of that year, the New York Times reports. Database managers were reportedly told the sequences would be updated and then submitted to another database, but Bloom can't find any evidence that happened. But he did manage to recover some deleted files from Google Cloud and reconstruct partial sequences from 13 samples. He says the samples appear to be more similar to coronaviruses found in bats than samples collected from the outbreak at a Wuhan seafood market, suggesting COVID-19 had been circulating for some time before it reached the market.
Analysis "suggests that the Huanan Seafood Market sequences that are the focus of the joint WHO-China report are not fully representative of the viruses in Wuhan early in the epidemic," Bloom writes in a paper, posted at bioXriv, that has not been peer-reviewed. It "seems likely that the sequences were deleted to obscure their existence," he writes. Bloom tells CNN that his study doesn't provide strong evidence for or against the theory that the virus leaked from a Wuhan lab. Other researchers, including evolutionary biologist Michael Worobey, say the recovered samples will advance work to understand the origins of COVID-19. Bloom—who notes that Chinese authorities destroyed some early COVID samples—says the deletion seems suspicious. "It certainly is strange at face value and really demands an explanation," Worobey says. (Read more coronavirus stories.)