A good explanation of typical reasoning used by those avoiding vaccination on More of Less (the shorter, World Service, edition).
You can hear it at
https://www.bbc.co.uk/sounds/play/p09rkn2zThe argument goes that if (numbers made up just now!) there are two people in hospital who are not vaccinated, and three who are vaccinated, then vaccination must be 50% more dangerous.
However, if there are 10 people unvaccinated people in the population, and 100 vaccinated people, then the hospitalisation rate is 3% in the vaccinated population, and 20% in the refusers.