Immunity is not the only answer.
Unless flubro attitudes make it the only answer.
Your lack of understanding of nature fuels your fears. Mankind was around long before any of this and yet we survived. Are you not even curious of how that worked?
Humanities immune system has disarmed more viruses than you can even imagine. In fact, you are full of them, right now. And they were the weights your immune system lifted to become strong.
Isolate those vunerable? Sure, of course. But the rest of us, especially the children, need to get back out there. If we do not it will be much more detrimental in the long run.