IT’S a startling fact that the Black Death killed about one-third of Europeans in the three years between 1347 and 1350. Had epidemiological surveillance been what it is today, that episode of bubonic plague would have generated some fabulous statistics. And had we known what we know now about plague and how it spreads, it would have been quite clear what we should have done about it.
But this is an exceptional case. In public health, it is rare for absolute numbers to suggest a defensible course of action. This is spectacularly illustrated by the current debate in the US…
