Dealing with pandemics at different stages of the life-cycle

From what I’m seeing, the coronavirus outbreak is gradually subsiding in China and other Asian countries, with the number of new infections dropping tremendously. This has also been accompanied by an easing of the restrictions which were put in place to deal with it. My question is how this works.

I would have thought that the necessity of restrictions would be based on the number of people thought to be carrying the virus at a given point. It shouldn’t make a difference what the number of new cases is versus old cases, and - more importantly - when considering the number of new cases, it shouldn’t make a difference whether the number of new cases is on the upswing or the downswing.

To the first point, I’m thinking it’s possible that the number of new cases is an indication of how many undetected cases are out there, so this number is more important than the nominal number of active cases, since that latter number refers to known cases only. But the second point is more puzzling.

But yet, that does not seem to be how the authorities are dealing with it. Why is that?

Most of the Asian countries also have much better testing and monitoring and social cohesion, so they have a (probably reasonable) expectation that they’ll be able to stay on top of decreasing number of new cases, contact trace, and isolate just who needs to be isolated.

There’s still a risk that things will go bad again, but you have to balance that against the huge cost of a massive lockdown.

The rate of increase/decrease is more important than the level. If # of cases are going up, you are on course for a catastrophe, so you have to implement more restrictions or face disaster. If # of cases is going down, then you know that the current restrictions are sufficient to force the disease down to zero, and you can experiment with lighter restrictions that will also do enough to keep cases decreasing but allow more economic activity.

The mistake of focusing on levels vs rates is why we had a bunch of people a month ago going around saying “Coronavirus is no big deal. There are only a few thousand deaths. Flu kills more than that each year.”