The 2000 guidance was based on expert opinion because there were no studies. Leap was published in 2015 and it gave the first level 1 data on peanuts. Anaphyla

The 2000 guidance was based on expert opinion because there were no studies. Leap was published in 2015 and it gave the first level 1 data on peanuts. Anaphylactic shock is scary and peanut fear was a big deal in the late 1990s but actual risk of harm was very low. The guidance was more about the psychosocial burden placed on parents when there was no guidance. Anxious parents have been studied, that mechanism is reasonably well understood and that harm can be quantified.