And those vaccines are which?, does the study allege any of the current vaccines does not provide immunity?, is so please put the quote and the study for that.
Otherwise this is a hypothetical... if x then y... when x is false in reality...
https://www.medrxiv.org/content/10.1101/2021.01.27.20240309v...
47 in link above is a study of the cruise ship, not what you think.
If you meant the actual link above, it clearly states vaccines give immunity but it might be waning, i.e: won't last, same as natural immunity
Best of luck, thought I might help with your logic, but I admit defeat there.