https://www.bloomberg.com/news/articles/2021-08-28/antibodies-waning-the-immune-system-has-a-backup-plan-for-that

Interesting read on natural immunity vs vaccine protection (not immunity) and how each changes over time. Draw your own conclusions

“ Wherry’s group found that memory B cells generated by the mRNA vaccines made by Moderna Inc. and Pfizer Inc. and its partner BioNTech SE appeared better at blocking virus variants including alpha, beta and delta, than those produced in response to a mild case of Covid-19.”

Above is what happens in breakthrough cases after full immunity has “worn off”