If we had a coronavirus vaccine, we’d deploy it immediately, right? A scary and lethal disease is leaping out at us, so we must get the globe lined up for its shots. Except, no, it doesn’t quite work like that.

The situation would have to be a little worse before vaccines got distributed widely, since everything has a cost, and everything is dangerous. Yes, even vaccines have a danger, however much the anti-vaccine crowd is deranged on the subject.