You don’t need to vaccinate 80% of the population to prevent deaths. You just need to vaccinate the vulnerable ( around 2.5 million people)and those over a certain age. Once that is achieved you can take off the brake and let covid run through the younger people who mostly just brush it off and don’t require hospital treatment. It’s not an all of nothing thing.
Looking at around 17m people if all those eligible for a flu vaccine would qualify for the COVID vaccine