[scoopertrooper]

I did a bit of googling and from what I can tell, Dr. Fauci has been has been messaging the higher figures since at least 1 December 2020. So starting from the period just before we've had vaccines approved for emergency use, Dr Fauci has been using the higher figures.

When Dr. Fauci was claiming lower figures: no vaccine had completed clinical trials; variants had not yet emerged; and governments were more willing to implement lockdowns, mask orders, and social distancing restrictions.

If he's guilty of anything, it is misleading the public into thinking he knows what the number is. Nobody knows what the real number is, there are so many confounding factors that it'll take years of research to come up with a decent estimate as to the real herd immunity level of Covid-19 immunisation.

This is a general problem in public scientific messaging. Science deals with uncertainty and nuance, but the fearful public seek certainty and simplicity. People in these positions don't always get the balance right (especially in a crisis), but I wouldn't impune somebody's reputation on that basis.