𝚜𝚎𝚕𝚎𝚊 
🇳🇱
@selea
Depends on the study. We arent talking about a single isolated study here but a pattern of evidence across several studies.
The only way to directly test for the number of infections prevented would be to intentionally expose people to the virus and see how they respond. Anything in the wild would have to be tested for indirectly and then we are back at the initial problem of post hoc proctor hoc for i direct inference.
The point is you can ask all sorts of questions we cant assert any answer about with any confidence. All we know is what direct evidence we have suggests yhe vaccine has no benefit against delta.
As i said before despite the fact that vaccine probably has no benefit of any kind id still advice people take it because it poses no risk and there is uncertainty about if it might help in some small way, so why not take it even if there is only a small chance it might help?
