Why is the work of Dr. Fauci critical to both homeland security AND emergency preparedness?

I inferred you are referring to Dr. Anthony Fauci one of America's most respected doctors.

Explanation:

Interestingly, Dr. Anthony Fauci has headed the National Institute of Allergy and Infectious Diseases for over three decades.

His abundant experience Is critical to fighting the emergence of infectious diseases in the United States which safeguards homeland security and emergency preparedness, especially against the ongoing pandemic.