re: 83% of Covid-19 deaths were among the Fully Vaccinated past month in UK

Your Oregon link shows that breakthrough cases were only 29% of total cases in the state.

80% of adult Oregonians have been partially vaccinated and more than 70% of adult Oregonians have been fully vaccinated. That suggests that far fewer vaccinated people have had COVID cases compared with their unvaccinated counterparts.

Surely that seems to suggest that breakthrough cases are fairly rare and hence mortality rates are going to be skewed higher (considering that people who are reinfected and hospitalized will be weaker than the average vaccinated person)?

So I'm confused how that shows that vaccines aren't working?

Vaccine -> Reduction in cases (Oregon data) -> Reduction in hospitalizations and deaths.

The mortality rate among hospitalized people doesn't matter, it's the hospitalization rate among vaccinated people that matters.

It's a bit disingenuous to look at mortality rates among people who've had breakthrough cases - people who've had breakthrough cases are not going to be a random sample of the population, they'll almost certainly be weaker and older than the vaccinated population in general.