no it reduces transmission; just as you can reduce speed in your car but that isnt stopping; it might lead to stopping but as long as you are moving you arent stopped. You are either stopped or moving; you can be moving a little bit or slowly but you cant be slightly stopped - its an absolute
Sort of the reverse to pregnancy - just as you cant be a little bit pregnant.
Now you could argue that it stops transmission in some people but not others but AFAIK that hasnt been claimed. I havent seen figures but usually it is argued that a reduction in viral load leads to lower transmission - although there are lots of other factors
In a population of ~70 million there will be billions upon billions of events in which transmission would be possible and it either "happens" or it is "stopped". And yes, binary, not a little bit "stopped" - the "recipient" or "recipients" does not get ill or display symptoms or develop a viral load or whatever other measure you wish to use.
The outcome of most of these events will be "stopped" as a result of an effective vaccine. "Effective" or "Stopped" does not mean 100% "Stop" events because that is unlikely in a large biological system with billions of such events.
With effective vaccination most transmission will be stopped upstream, because much less of the population will be carrying an infection which could be transmitted. From a population perspective transmission has been effectively stopped.
We are not going to agree on this and is probably off topic for the thread. I've put forward my argument so I'll leave it there.