In short, the rates described are complete fiction since they are not and can not be conducted in a controlled environment and studies that take that approach are generally considered exceptionally weak due to the aforementioned fallacy.
For example, how do you know those numbers are due to the vaccine and not some other property that is unique to the group of unvaccinated people? One very reasonable assertion is simply that unvaccinated people do not generally take precautions to avoid the virus (like wearing a mask or washing their hands as often) and thus that, rather than the vaccine, is the reason for the difference in numbers. Thus the fallacy I mentioned.
@Nobody@freeatlantis.com @zleap