I'm confused about some of the implications regarding crowd infections.
Certainly for some of these -- say, Chicken Pox -- we know that early and controlled exposure is preferable to a first case later in life. And that the cycle of herd immunity in survivors leads to endemicity and less deadly strains.
It seems like both things can be true: it's best not to get infections at all, but if you live in a world where you will get infected, doing so early and outside a correlated epidemic can be advantageous. And, while our immune system evolved for a different social density, it still plays a critical role in mitigating the long-term collective impact of crowd infections.
We used to think that "early and controlled exposure is preferable to a first case later in life" for chicken pox, but AFAICT that's no longer widely accepted in most western countries. Chicken pox in children can lead to serious complications in some cases, including bacterial skin infections, pneumonia, and encephalitis. The virus remains dormant in the body and can reactivate later in life as shingles. Now that there's an effective 2-shot vaccine, that's the recommended approach.
Certainly for some of these -- say, Chicken Pox -- we know that early and controlled exposure is preferable to a first case later in life. And that the cycle of herd immunity in survivors leads to endemicity and less deadly strains.
It seems like both things can be true: it's best not to get infections at all, but if you live in a world where you will get infected, doing so early and outside a correlated epidemic can be advantageous. And, while our immune system evolved for a different social density, it still plays a critical role in mitigating the long-term collective impact of crowd infections.