Abstract
Contrary to popular belief, population-wide preventive measures are rarely cost-reducing. Yet they can still be cost-effective, and indeed more cost-effective than treatment. This is often true of preventive measures that work by slightly reducing the already low risks of death faced by many people. This raises a difficult moral question: when we must choose between life-saving treatment, on the one hand, and preventive measures that avert even more deaths, on the other, is the case for prevention weakened when it works by reducing many healthy people’s already low risks by a further tiny amount? I argue the answer is no