POLLY TOMMEY: “What is the definition of unvaccinated during COVID in a hospital?”

HOSPITAL NURSE: “It's either unvaccinated, meaning you have not had a vaccine at all, or it could be that you have had one of the vaccines.”

So when studies claimed the “unvaccinated” had worse outcomes, were they really comparing unvaccinated vs. vaccinated or just early-dose vs. late-dose?
If the categories are muddy, how clear can the conclusions be?