I think that due to Fauci's age and his exposures (guessing here but he is in contact with medical people all day right?) he is probably in a high risk group and has been throughout the pandemic.
He has tested positive but has not been sick or been hospitalized.
So I would say his vaccinations probably did their job.
I was working in the community, going into people's homes throughout the pandemic.
At one point my city and one section of it where I worked were the "hottest" for number of new infections in the world.
I never got COVID. i was vaccinated, of course it is impossible to know if the vaccinations helped me, but I was glad to have them.
We all interpret the information in our own way.