1. 'Saving lives' sounds, as it is meant to, like a moral high principle, but, if you want to do that, best turn to God. Away from soteriology, what saving a life really amounts to is postponing a death. So life-years gained is a more natural metric for policy purposes.

2. At the next stage on, it can be noted that, in the perceptions of most of us, and as revealed by our behaviours, not all life-years are equal. Personally, I lean a little toward the Kingsley Amis end of the spectrum on the differential valuation of life years:

3. “No pleasure is worth giving up for the sake of two more years in a geriatric home in Weston-Super-Mare.” But such valuations are matters of (changing) personal preference (Weston looks better the older you get), and de gustibus non est disputandum.

4. Govts making public choice decisions do, however, have to work, implicitly or explicitly, with 'quality of life' valuations capable of commanding wide public consent. Hence, the development of the health economics metric of the QALY, the quality-adjusted life year.

5. The QALY metric renders commensurable things that some, displaying considerable hypocrisy, claim to be incommensurable (the hypocrisy comes from the implicit life/convenience valuations they themselves make whenever they drive their kids in a car or cross a busy street).

6. The bottom line in all this is that, for policy purposes, it is productive to think of any 'economy' vs 'saving lives' decision in terms of impacts on QALYs, over a time-period sufficiently long to encompass impacts on all the current living.

7. That's a hugely difficult exercise to do. We are now well familiar with the wide range of possibilities on the epidemiological side, but what about the impacts (measured in QALYs, not £s) of, say, a crashing economy? They are also highly uncertain, but in what range?

8. To give a sighting shot of the sort of numbers involved: on current NICE valuations a 1% reduction in GDP for a period of one year would, if the accounting were done in QALYs rather than £s, equate to a fall of around 1 million QALYs.

9. BTW, an interesting exam question might be to assess the impact of CV19 on the aggregate endowment of QALYs of the existing UK population as a whole. It gives a ecosystem-wide perspective on that impact which might be helpful in keeping a sense of proportion in all this.