David Aaron Kessler is an American pediatrician, attorney, author, and administrator serving as Chief Science Officer of the White House COVID-19 Response Team since 2021. Kessler was the commissioner of the Food and Drug Administration (FDA) from November 8, 1990, to February 28, 1997. He co-chaired the Biden-Harris transition’s COVID-19 Advisory Board from November 2020 to January 2021 and was the head of Operation Warp Speed, the U.S. government program to accelerate the development of COVID-19 vaccines and other treatment, from January to February 2021.