I did a little digging a while back on if the COVID vaccines reduce transmission and they do to some extent. Here is a review of the clinical trials -
https://assets.publishing.service.go...pid-review.pdf
It’s quite long and very dull as epidemiology studies tend to be but the key pages are from page 8. The two measures are SAR which is the rate of spreading to others and RR which is risk reduction for spreading to others compared to unvaccinated. The effect is modest but seems real. The study also looks at viral load which is how much virus is present in someone in COVID and the load was always lower in the vaccinated which explains why the chance of transmission is less.
By the way, if paracetamol was launched now, it would NEVER be approved. The dose gap between useful pain killing and toxic effects is way to small for a modern drug.