It's also not known to be correct. https://theconversation.com/early-exposure-to-infections-doesnt-protect-against-allergies-but-getting-into-nature-might-12660

It's also not known to be correct. https://theconversation.com/early-exposure-to-infections-doesnt-protect-against-allergies-but-getting-into-nature-might-126603 https://theconversation.com/early-exposure-to-infections-doe... Current researchers advise to avoid the phrase "hygiene hypothesis" entirely, because it's misleading, and the most recent formulations are not that we need more early exposure to bad things but that we need more early exposure to good things.