This makes sense to me as my son developed his allergy the exactly
same day he had his first shots (at 4 months). At first I thought
it was just a reaction to the shot (the anaphylactic reaction) and
not to the bottle. On the other hand, I have heard that some
German pediatricians wait to give vaccins until at least 1 year as
there is some evidence that most allergies are triggered by the
early shots.

Angela