Dr. Rick Bright is an international expert on vaccines with a lengthy work history in the field. His expected testimony comes after he filed a whistleblower complaint last week alleging he was removed from his post in retaliation for opposing the broad use of hydroxychloroquine, a drug frequently touted by President Donald Trump as a treatment for Covid-19.

Bright had led the Biomedical Advanced Research and Development Authority, part of a Department of Health and Human Services office that has been central to the response to the coronavirus outbreak, since 2016.

As BARDA's director, Bright oversaw "the advanced development and procurement of medical countermeasures against an array of threats to national security and the public's health, including chemical, biological, radiological, nuclear threats and pandemic influenza, and emerging infectious diseases," according to an archived webpage of his official biography.

An HHS spokesperson told CNN at the time of his departure in April that Bright would be leading a public-private partnership on vaccine development and treatment. But Bright has yet to assume that new role after he filed a whistleblower complaint alleging that his early warnings about the coronavirus were ignored.

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