There’s been a lot of rather loose talk recently about the distinction between “mitigation” and “suppression” which are really just expensive words obscuring the simple difference between “make it grow less fast” and “make it shrink”.
The basic fact is that in most of the world, the number of as yet undetected cases of COVID-19 may already be so great as to overwhelm our intensive care capacity when the expected percentage of them become critical. This means that we need NOW to do whatever we can to minimize infection rates and actually make the infected numbers go down. Making it grow less fast is not enough.
But even making it go down is not enough. If we start it going down next week that won’t mean we can just relax. We’ll have to keep it going down for some time. And even if we eventually make it go down almost to zero, that will still not be enough if there are still parts of the world where it exists more strongly. We will need to be able to catch and stop any new cases that come in through our borders or that pop up from the few remaining undetected cases at home.
But the other side of this coin is that we may not have to eliminate it completely. If enough of the population (in this case apparently about 70%) is immune, then any local outbreak is expected to shrink. (This is sometimes referred to as having “herd immunity”.)
One way to make people immune would be by vaccination, but we don’t yet have a vaccine (and don’t expect one for at least 18 months). Another source of immune people might be those who have had and survived the disease. So the best bet might be not to try to kill the disease completely, but rather to keep the number infected at a constant level that is just below what would overload our intensive care capacity.
In the language of suppression and mitigation, this would be to suppress as quickly as possible until the acute care need becomes manageable, and then relax restrictions just enough to keep making almost full use of our IC facilities until either the “herd immunity” level is reached or an effective vaccine is developed.
See: COVID-19 « alQpr