Kessler, who is currently the co-chair of the Biden transition’s coronavirus task force, will help lead Operation Warp Speed in the new role, helming the group that began under President Donald Trump to speed up vaccine development and distribution.
Kessler previously led the FDA under Presidents George H.W. Bush and Bill Clinton.
Slaoui will stay on for another month to “ensure a smooth transition,” a Biden transition official told CNN earlier this week.
This story has been updated with additional background information.