That’s the story we’ve been sold. I recall it from my schooling in the 80s.
True?
I buy it. Anyplace exposed to a disease regularly usually has far better resistance to it than virgin populations. We happen to be in a period where we’ve got good nutrition, hygiene and treatments to weather even “novel” stuff. That’s probably why the mRNA crap was foisted on us, to get around innate and innovative toughness of western populations.