The origin of the SARS-CoV-2 virus that causes Covid-19 remains unclear, but recent revelations reinforce the likelihood that the true source was a lab leak from the Wuhan Institute of Virology (WIV).
A letter from Lawrence Tabak, the National Institutes of Health’s principal deputy director, to Kentucky congressman James Comer confirms that the NIH funded research at the WIV during 2018–2019 that manipulated a bat coronavirus called WIV1. Researchers at the institute grafted spike proteins from other coronaviruses onto WIV1 to see if the modified virus was capable of binding in a mouse that possessed the ACE2 receptors found in humans—the same receptor to which SARS-CoV-2 binds. The modified virus reproduced more rapidly and made infected humanized mice sicker than the unmodified virus.
