Documents released yesterday by the National Institutes of Health (NIH) appear to contradict previous claims by the EcoHealth Alliance regarding the subject of experiments on bat coronaviruses in Wuhan, China, raising further questions over whether U.S. government funding contributed to so-called “gain-of-function” research.

In a letter to Representative James Comer, Ranking Member on the Oversight and Reform Committee, the NIH provided additional information and documents regarding NIH’s much-scrutinized grant to EcoHealth Alliance.

“The limited experiment described in the final progress report provided by EcoHealth Alliance was testing if spike proteins from naturally occurring bat coronaviruses circulating in China were capable of binding to the human ACE2 receptor in a mouse model,” the letter, signed by NIH Principal Deputy Director Lawrence A. Tabak, states. “In this limited experiment, laboratory mice infected with the SHC014 WIV1 bat coronavirus became sicker than those infected with the WIV1 bat coronavirus.”