This article does a good job of breaking down what happened with Provincetown. And probably about as good of a "real world" scenario of actual results as we'll get. They've been doing significant contact tracing and a group of middle to upper middle class gay men are very likely to follow up this situation by getting tested since HIV has made most of us very big fans of medicine and the importance of proactively looking after one's health.

My takeaway from the data from Provincetown is actually quite good:

Almost everyone was vaccinated, both local residents and vacationers. Estimated that as low as 1% weren't. All the venues where crowded parties were happening were requiring proof of vaccination.
60,000 tourists bringing germs from all over and swapping them in close ("carnival") quarters;
1,000 total cases, almost all mild or symptomless, so Pr(+ test) = 1.7%
750 cases among vaxed, so Pr("Breakthrough") = 1.25%
250 cases estimated among unvaxxed, so roughly 50%
7 hospitalized, so Pr(serious) = 0.0117%
And most importantly ZERO DEATHS

The ultimate takeaway is that the vaccines absolutely worked, and worked quite well.

https://www.washingtonpost.com/healt...ovid-outbreak/