Earlier quoted context omitted.
No, it's a myth (albeit a popular one) that the human immune system benefits from being "toughened up" by actual pathogens . It's more about calibration by non-pathogens we co-evolved with. https://www.pnas.org/doi/10.1073/pnas.1700688114
What about the isolated populations, e.g. Sentinelese that are documented to die because they don't have the immune system developed to protect themselves against the viruses rest of the World has? Although I would agree that 10 years later in your life is unlikely to create an issue. > The Andaman and Nicobar Islands Protection of Aboriginal Tribes Regulation 1956[9] prohibits travel to the island, and any approach…
A: What behaviors or environments lead to adult immune systems calibrated to minimize autoimmune dysfunctions.
B: Comparing populations that already/ haven't developed inherited countermeasures against certain diseases.
C: (In some cases) Specific pathogens where it is less-damaging to encounter them at different phases of life.
In particular, I'd point out that sometimes a population strong against a particular disease does not necessarily have "better" immune systems... Sometimes it's literally survivorship bias, where all of the vulnerable individuals they used to have already died in tragic ways.