I don't know if it will surprise you to learn that infants are giving the Hep B vaccine less than 24 hours after being born. And children now take twice as many vaccines before their fifth birthday than when I was a kid (I am 38). I don't know if it's related but it seems messing with the immune system before a baby has even had their first drop of breastmilk just seems crazy and allergies are an immune reaction.

I have developed anaphylaxis to shellfish and dairy in the past couple years. I have no idea why, but my mother developed anaphylaxis to shellfish in her 30's, too, so part of it is likely genetic. There are alot of theories from increasing homogeneity of food supply (what happens when instead of 20 peanut or wheat varieties, there is only one. Someone recently posted about rising hazelnut allergies in Europe - that is their peanut equivalent, meaning it's in everything. I am healthier than I have ever been and suddenly I have to carry a stupid Epi-Pen everywhere I g. I have had a bunch of vaccines in my 30's (Rhogam for RH factor, rabies, tetanus). Who knows

ETA: There has been pushback recently on this stuff, because many kids who test positive for allergies don't actually have a reaction when they eat that food. So, just becasue a kid has been diagnosed with a "deadly" allergy does not mean they actually are in any danger. I think allergists will get better about doing actual food challenges to make sure it's a real thing.