The first from the NYT discusses the fallacy that childhood illness somehow builds up the immune system making them healthier adults. Rather, it emphasizes correctly, that exposure to lots of harmless antigens seems to be the key to making kids less susceptible to asthma and allergies, not exposure to harmful ones. In other words, let your kids go outside and eat dirt, but don’t take them to chicken-pox parties (vaccinate them instead).
In a similar vein, Slate has an articleon eating more crap. While the point is made more carelessly, the idea is the same, that exposure to common harmless antigens may be protective for later exposures in preventing auto-immunity and decreasing severity of illness.
It reminds me, of All Creatures Great and Small, when Herriot is discussing the children of the local “knacker man” Mallock. The man spent all his time cutting up, and processing diseased carcasses of farm animals, and Herriot remarked that his kids, despite being surrounded with all the stinky filth imaginable, he were the healthiest children in the district.