In a letter to lawmakers, the US National Institutes of Health says that one of its grantees did not immediately report that it had developed a coronavirus that was more infectious in mice, Science reports.
It adds that EcoHealth Alliance, which was working with the Wuhan Institute of Virology, was studying coronaviruses found in wild bats, including the spike protein that the viruses use to attach to cells. According to Science, the researchers made chimeras in which the spike protein from these bat coronaviruses were expressed in a previously known bat coronavirus called WIV1. One of these chimeras, it adds, was then more infectious in mice.
As NIH's Lawrence Tabak tells lawmakers, the agency had determined that the work was not gain-of-function research involving "enhanced pathogens of pandemic potential," and that this was an unexpected result. However, Tabak adds that the grantee did not report the result to NIH within the timeframe required.
He further emphasizes, though, that the viruses under study were evolutionarily distant from SARS-CoV-2 and could not have developed into it.
Still, Science notes, though, that the revelation is "giving fuel to critics of NIH who say agency leaders have not been upfront with Congress about the work NIH was supporting in China, many of whom believe WIV could have created SARS-CoV-2."