This article (this article is a preprint and has not been peer reviewed yet) shows a multicenter chart review which identified the cases of COVID-19 which required hospitalization and then, the vaccination status of the patient
This study, showed that the rate of hospitalization in unvaccinated people was 423/100000 and the same rate for vaccinated people was 26/100000. There is a 17X difference.
The study does not address the potential loss of protection over time. It is possible that the rate of hospitalization for vaccinated people would increase as months pass.