In fact a very small group age >75 is the real contribution of the vaccine success. For all the others is more or less none.
This is why a famous study could show that real vaccine protection is just 1% for death.
Rewritten - the way most people would see it:
In fact a very small group age > 75 constitute the real at risk most likely to die. For the others, the risk is lower.
The real risk of death averaged over populations is 1% which is why a famous study shows that the vaccine prevents about 1% of deaths.