You can drive the suggested analysis here as far as you want, but ultimately, you will lift your head and realize it's all useless for actual policy making wrt COVID-19.
The ultimate answer is that there is no ultimate answer. Abstract mathematical modeling for these sorts of questions is therefore mostly useless. Useful answers come from going in and dealing with lots of messy particularities in a very messy reality.
I like to think that this problem with quantitative rationality, where you build a model about one thing and get a very precise answer, but then realize your answer is really just another question, is exactly what's being alluded to in "42".
(e: moved this sentence to the bottom of my comment because it seems to be causing some distracting hostility: "This sort of thought process is exactly how you go about convincing a wise person to just give up on the whole hard core rationality project. It's an unintentional strawman.")