That's not what he actually said, which I would know, because I transcribed the interview myself.
What you posted is someone else's reinterpretive spin on it, possibly including what Fauci would have been pressured into saying by people with agendas.
The interviewer pressed him on it, and he held his ground.
He's probably an MD/PhD, he already knows all the objections, and he stood by his point.
I'm aware of the objections, but I'm also aware of other factors in play and what they seek.
I consider his straightforward statement sufficient.