if you catch Wuhan original recipe, the vaccine has the best protection because that’s what they were designed for
if you catch new and improved delta/delta plus, your odds are slightly reduced because the virus has mutated defensive mechanisms against natural antibody detection called immune escape. The vaccines boost your antibodies.
I read somewhere the average age of a breakthrough infection is 72 with two or more pre-existing conditions, for what it’s worth.
The study cited was done in 2020, and the Delta wave shows 'jabbed' victims are now infectious, like the cruise liner with all-'jabbed' crew and passengers contracting CoVID. So much so the CDC changed rules, again, defining 'vaccinated' as only after 14 days; if you get CoVID within that period you are 'unvaccinated', even though you have the spikes in you.