I'd still like to know more about WTF Fauci was talking about when he said the bit about the vaccine (I think the RNA based one) not stopping the disease, but stopping the symptoms. Sounds like a leaky vaccine to me. How is that better if a lot of people get that vaccine and then act like the pre-symptomatic spreaders? I really wish he'd have explained that more in depth.
I didn't hear his particular quote BUT this is a common statement at the moment, as the actual study data has not been released.
There are diseases where your immunity kicks in so rapidly that the virus can't multiple much at all.
There are other diseases where the virus has some time to multiply and shed, but your immunity kicks in about the same time and therefore you don't have much, if any, documented disease.
If the Covid vaccines only reduce shedding a little and reduce symptoms a lot, then you won't get as much of a herd immunity effect.
If they stop the disease almost entirely (ie so little viral replication that people are testing negative and aren't infectious) then it will be easier to reach a herd immunity status.