That’s the difficult part, but that’s the job of the public health authority. Same thing with missed semesters of a school. How many add up to an 80 year old dying? And so on and so forth. I don’t envy those that have to do this arithmetic, but it can’t be avoided.
I don't see how it is arithmetic nor the job of a public health authority. It's a philosophical, ethical and political issue.
There are bounding conditions, like research showing that job loss increases rates of suicide. [1]
But we still argue about whether it is fair to treat the life of a 12 year old as more valuable than the life of a 92 year old. So it isn't just arithmetic.