I've tried to look at a few bellwether places that have high vaccination to understand Delta and herd immunity. Namely I've been looking at San Francisco, Vermont, Iceland, Gibraltar, the UK, and Israel. But Gibraltar is one of the more confusing ones.
Back in March the media was declaring they had vaccinated their entire adult population. And due to Spanish day workers their doses administered exceed 100% vaccination. But clearly unvaccinated resident adults still exist in there.
Unfortunately I can't seem to get any clarity on how many unvaccinated remain. They haven't started vaccinating children under 16 yet either.
We know breakthrough infections can happen and possibly transmit with Delta. Most of the vaccine doses in Gibraltar have been Pfizer unlike the UK where AstraZeneca is the majority.
Cases have spiked recently there, but fortunately hospitalizations and deaths have remained low. Gibraltar gives a sobering view of herd immunity with Delta, but it is honestly hard to get a good picture of the situation given so many visitors and day workers.