The difference between fearmongering and warning lies in whether the dangers being warned of materialize after the warnings are ignored.

In West Africa, early confidence was misplaced, and warnings were slow to go out. Anybody who sounded the alarm, if there was anybody, must have been dismissed as a fearmonger.

Here, and for sound reason, we expect that notwithstanding this very unfortunate lapse, our methods will prevail and without any extensive chains of transmission. That expectation is reasonable and well grounded in past experience. But it is not a law of nature. There is an outside chance that we are overconfident. The precautionary principle, famously invoked by Pascal, goes that when the consequences of being wrong are incalculable, it’s a bad idea to proceed as though you can’t possibly be wrong, even supposing the odds are stacked heavily in your favor.

For now, we had best proceed on the premise that we just might have underestimated the risks. Perhaps the protocols are not so easily observed by rookies as they are by veterans, for instance.