I think you have evolution backwards. There only needs to not be a reason we need it to survive long enough to reproduce. Or more probabilistically, there needs to not be a significant reproductive benefit to it.
And bear in mind that most people don't have a problem surviving colds and the like long enough to reproduce even with no vaccines at all, and that was probably more true for much of our evolutionary history when we were living much more isolated lives, and not cohabiting with chickens and pigs.
At scale, yes. Because human males have significantly longer fertility periods than females, the specific adaptations of men who are healthier into later life can be passed onto offspring. The same applies to women who reach menopause while they're still healthy are able to continue caring for family without the risk of expanding the population, albeit for their offspring.
While human evolution is not predictive, it has selected for a wide variety of survival-associated adaptations beyond the mere individual.
>There only needs to not be a reason we need it to survive long enough to reproduce.
Humans had life expectancy even shorter than our fertility period until recently and they developed as social species hundreds of thousands years ago, for which living beyond fertility period is beneficial (grandparents were invented by evolution too).
> And bear in mind that most people don't have a problem surviving colds
That’s modern people with access to antibiotics etc.
> that was probably more true for much of our evolutionary history when we were living much more isolated lives, and not cohabiting with chickens and pigs
For much of our evolutionary history people were eating animals, getting viruses with them.
> That’s modern people with access to antibiotics etc.
Antibiotics don't help against viruses like colds. And we live a life that is has a higher degree of social connectivity than our ancestors, allowing for faster spreading of disease, so we're arguably worse off.
> Humans had life expectancy even shorter than our fertility period
That's largely due to infant/child mortality. Once you reached reproductive age, life expectancy was roughly 50, plenty of time to have plenty of kids.
Yes, and to get there we use immunity that is activated on demand. Clearly that was better from evolutionary perspective than preactivation or always-on.
> Yes, and to get there we use immunity that is activated on demand. Clearly that was better from evolutionary perspective than preactivation or always-on.
I don't think you understand evolution. Neither needs to be "better" for anything other than survival to reproduction. Evolution isn't min-maxing in a video game.
I don’t think you understand it, if you cannot connect the dots. And of course “survival for reproduction” is oversimplification of what’s actually happening. Chances for survival to reproduce of some individuals are greatly influenced by survival of their relatives in the same group. The traits that help whole group to survive will win in natural selection, including those that extend survival beyond what’s necessary to reproduce to what’s beneficial for the group.
Might be as simple as cost/effect in resource-constrained environment.
Inflamation uses up resources. When we were hunter-gatherers and had to survive ice ages - it wasn't a good idea to waste calories and vitamins just in case.
Better for 3 people out of 30 to die of flu than for all 30 to starve.
Nowadays the optimal trade-off might be completely different.
If something clearly helps survival and not an improbable thing to develop, the chances are high we would already have it. But we don’t and most species don’t. It is not the default, there likely exists a reason why.
> If something clearly helps survival and not an improbable thing to develop, the chances are high we would already have it.
Well sure, but "not an improbable thing to develop" is doing a lot of work there. Again, everything complex is "improbable to develop," in the sense that evolution takes a lot of time and is very path dependent.
We could have paper shredders, blenders, toasters, water taps, and so on that just ran all the time, but our utility bills would be ginormous. Same thing for our bodies.
So does getting infected over and over. Much worse damage. Evolution isn't some magic thing that gives you the most optimal creature for a given metric. The only metric is procreation. Not longevity. Not a pleasant life.
And bear in mind that most people don't have a problem surviving colds and the like long enough to reproduce even with no vaccines at all, and that was probably more true for much of our evolutionary history when we were living much more isolated lives, and not cohabiting with chickens and pigs.