Congress controls the funding for the National Institute of Allergy and Infectious Diseases, run by Dr. Anthony Fauci as part of the National Institutes of Health.
Congress approves overall funding for NIAID and its timing, and authorizes funding for each particular program the NIAID wants to support.
Periodic funding requests from the NIAID cross many desks before being considered by Congress: first those at NIH, then the Department of Health and Human Services, then Office of Management and Budget, which sends requests to the president. Each year the president proposes a budget to Congress, which Congress then must approve.