Since the first mRNA vaccine against COVID-19 was authorized on December 11, 2020, studies have shown that unvaccinated people are at five times greater risk of getting infected and 10 times greater risk of hospitalization or death from COVID-19 than those who are fully vaccinated.
https://www.nationalgeographic.com/science/article/how-booster-shots-can-help-protect-you-from-omicron