Fauci, and all others directly involved, would be guilty of using a weapon of mass destruction. Somehow the virus was weakened, but that would not make a difference in the crime committed.
18 U.S. Code § 2332a - Use of weapons of mass destruction
(a) Offense Against a National of the United States or Within the United States. A person who, without lawful authority, uses, threatens, or attempts or conspires to use, a weapon of mass destruction:
(2) against any person or property within the United States, and
(D) the offense, or the results of the offense, affect interstate or foreign commerce, or, in the case of a threat, attempt, or conspiracy, would have affected interstate or foreign commerce;
shall be imprisoned for any term of years or for life, and if death results, shall be punished by death or imprisoned for any term of years or for life.
Definitions. For purposes of this section, the term “weapon of mass destruction” means:
(C) any weapon involving a biological agent, toxin, or vector
https://www.law.cornell.edu/uscode/text/1/2332a
18 U.S. Code § 178 - Definitions
(1) the term “biological agent” means any microorganism (including, but not limited to, bacteria, viruses, fungi, rickettsiae or protozoa), or infectious substance, or any naturally occurring, bioengineered or synthesized component of any such microorganism or infectious substance, capable of causing
(A) death, disease, or other biological malfunction in a human, an animal, a plant, or another living organism
https://www.law.cornell.edu/uscode/text/18/178